In Shaman King a trio of X LAWS sacrifice themselves to tell their comrades the weakness of the Big Bad, Hao. Before they die and reveal Hao's weakness, Hao himself reveals his secret shocking everybody.
Fullmetal Alchemist double-subverts this with the death of Fu. After Wrath wounds him and he realizes that he cannot fight him for much longer, he rips off his shirt to reveal four explosives and lunges at Wrath to kill them both... but Wrath just slices the fuses off of the explosives with his sword, rendering them harmless and slicing open Fu's belly in the process. Buccaneer, who had already been fatally wounded, seizes the opportunity and stabs Wrath through Fu, taking advantage of the one blind spot in Wrath's otherwise perfect vision to seriously injure him.
In the 2003 anime version, a similar event occurs, though they are trying to hold off Lust and Gluttony. The end result is the same, though, and they are subsequently eaten by Gluttony.
Favored tactic of the X-Laws from Shaman King against Hao. First attempt makes him stronger, the second decimates them.
Batist in Full Metal Panic! dramatically sets his M9 for a ten second self destruct to take down Gauron, makes a heroic speech, and immediately charges and tries to grapple him... only for Gauron to shoot his AS in half at the last second and teleport away, well outside the blast radius.
Happens all the time in Dragon Ball: Mutenroshi (Who later in the Saiyan arc openly admits that such losses are both senseless and tragic) and Chiaotzu against King Piccolo, Chiaotzu again and Tenshinhan against Nappa, Vegeta against Majin Buu, and Krillin against Majin Buu. Of course, it's Dragonball, so they all get better, but still.
Android 16 didn't, sadly. His plan to bear hug Cell and just blow the living daylights out of him failed when it was revealed that his self-destruct mechanism was removed when Bulma reconstructed him. And by the look on Cell's eyes, it might, might have worked had he pulled it off.
Subverted into a Heroic Sacrifice. When 16 was broken apart, he could still theoretically be repaired, but then he had Mr. Satan throw his head towards Gohan and Cell, and arranged for Cell to squash his head, to inspire Gohan to attain the next Super Saiyan level.
Goku pulled one off against Cell too, by teleporting to King Kai's planet with him shortly after Cell decided to self-destruct. Cell's core survived, allowing him to regenerate, AND become EVEN stronger because of his Saiyan genes. It's not completely senseless, though; Goku did save Earth.
Which means that even if 16's original plan had worked, the outcome would've likely remained the same, except that 16 wouldn't have been around to inspire Gohan.
Averted in Gall Force 2 where the latest Catty plans to get the team through a blast door by detonating her own internal power supply. At the last moment the leader of the team points out that there's another blast door beyond it. Fortunately, Luffy then shows up in a Big DamnHumongous Mecha.
Happens several times in Fist of the North Star, most notably when Rei attempts a Heroic Sacrifice against Raoh, only to have him counter it in a laughably easy way. Juza also tries to give his life to break Raoh's arm, only to have it completely fail. Raoh seems to enjoy evoking this trope.
Miyuki/Rapier in Tekkaman Blade self-destructed to try to take out Sword, Lance, and Axe. It didn't work, although she did force them to retreat, so it's only a partial example.
But he DID fail to take over the planet, and to assassinate John Paul II.
The death of BlackWarGreymon towards the end of Digimon Adventure 02 partially counts as this; sure he managed to protect Cody's grandfather, but then he attempted to use his body to stop Myotismon from entering the Digital World again. Too bad that's exactly what happened a few episodes later.
To make matters worse, the gate he did manage to seal is one that would have been useful for hte heroes to have open once that happened!
Neon Genesis Evangelion. In the series, there's Rei II's death, although "if she died, she could be replaced!" thanks to cloning. Aside from that, Senseless Sacrifice basically sums up the entire plot of End Of Evangelion: so many sacrifice so much to prevent Instrumentality, and it happens anyway. On the other hand, Gendo has made countless sacrifices to achieve Instrumentality, only for his son to reject it, and there's still the possibility the rest of humanity will as well, so maybe it's a Senseless Sacrifice all around.
At least Rei destroyed an Angel and saved Shinji. That has to count for something.
In the very first episode:
General 1: We sacrificed a whole city for nothing...
Well, Madlax got out of her depression quick enough—by running off with the woman who killed Vanessa. That's some Karma Houdini we're talking about here.
In Zeta Gundam, Henken uses the battleship Radish as a shield in an attempt to save Emma and the Gundam Mk-II from Yazan and his Hambrabi. Yazan kills him and later kills Emma.
In Victory Gundam there are a few examples but the most egregious by far is Oliver Inoue's, who manages to destroy a V2 Gundam to deal negligible damage to the enemy, leaving behind a pregnant wife.
Gundam 00, season one. Neil Dylandy, the original Lockon Stratos, combines this with essentially his Crowning Moment of Awesome. It was tough to swallow, but forgivable... until Ali Al-Saachez returns in season two, with no preamble, and more sadistic than ever.
Even if it didn't finish him off, it did take him out for the rest of the season, which in turn allowed the rest of Celestial Being to survive the final battle. On the other hand if Lockon had saved himself he might have lived a few more days but with Ali's help the UN forces would have exterminated Celestial Being and everyone would have died anyway. Though if it weren't for Lockon inexplicably failing to use trans-am, he might not have needed to sacrifice himself.
Averted in Mobile Suit Gundam SEED, where in the final episode, Athrun Zala plans on destroying the Kill Sat GENESIS by self-destructing their Gundam in its core. However, Cagalli manages to talk the person out of it, and together they infiltrate GENESIS' command center and find its own self-destruct function, which would have turned said sacrifice into a rather painful version of this.
Fushigi Yuugi has a huge Tear Jerker in the form of the death of Nuriko. Rather than simply wait for Mitsukake, who could have cleared up his injuries with a touch, he decides to use the last of his strength to move a huge boulder, and dies of the strain. The reason it's a Senseless Sacrifice? The boulder isn't actually blocking the cave entrance it's in front of. There's enough room to just walk around it. There are even skeletons already inside the cave when the rest of the Seishi finally get in!
YuYu Hakusho opens with a senseless sacrifice by the main character. It appears as though he saved a child from being run over, but the Grim Reaper later remarks that the car would have veered out of the way if not for the confusion of Yusuke jumping into the street to push the child out of the way.
To add insult to injury, the child actually took more damage from being pushed onto the ground than he would have taken otherwise. Nice Job Breaking It, Hero.
Botan: "The kid would've survived without a scratch without your intervention, but thanks to your meddling, the kid gets scraped up, and you die. Haha, way to go, moron!"
Subverted however, in that while the sacrifice was useless in it's intended purpose, it ultimately allowed Yusuke to turn his life around (once he got it back, of course).
It also gave him the opportunity to come back in the first place. The powers that be never expected someone like Yusuke to save a kid at the cost of his own life, so he wasn't supposed to die at that time. It's the only reason Yusuke was given the chance to earn a resurrection.
In the manga version of Elfen Lied, doomed clumsy girl Kisaragi is informed by Kurama that she must be sacrificed in order to kill Lucy, who has taken her hostage. She agrees to this readily, owing to her deep feelings for her boss. Arguably, the anime, wherein Lucy simply kills her ASAP, leaving a dumb look on the poor girl's floating severed head, owns the shock value. But when Lucy is able to use her hostage's death to confuse things just enough to help ensure her escape, she does not hesitate to taunt the hell out of Kurama, stating 'Her Death Was Useless!'.
Though Kisaragi's death does inspire Kurama not to try sacrifice anyone else to stop Lucy. This ends up saving Nana's life later.
Jim Crocodile Cook in Yu-Gi-Oh! GX. It's not entirely pointless, but it only reveals the strengths and weaknesses of Haou, Judai's super powered evil side so that O'Brien can make a proper heroic sacrifice.
The death of Norris Packard in The 08th MS Team. He dies destroying the Guntanks being escorted by the 08th Team, clearing an escape path for a ship full of wounded soldiers. Unfortunately, Ginias decides to punctuate his decent into madness by violating a temporary ceasefire, so the Federation retaliates by shooting down the ship with a sniper MS.
A borderline case happens to Ran in a Case Closed movie where her, Conan, the Shonen Tantei, and other kids are trapped in a virtual world in 19th century London. Any one who get mortally wounded in game are deleted and the only ones left are Conan, Ran, and a random rich kid. Ran has just been captured by the in game Big Bad and a showdown between him and Conan begins on top of a moving train that is going out of control. Ran, remembering Shin'ichi words, decides to save the two boys by jumping off the train into the abyss, deleting herself and taking the big bad with her. Unfortunately, she inadvertently caused Conan to fall into a Heroic BSOD and took away the only means to save them and beat the game (They needed her extra strength to take out the bolt connecting the cars so that the car they were on slows down while the rest ends in oblivion.) It takes a Deus ex Machina / Chekhov's Gun to snap Conan out of it and save the day.
In Transformers Armada, towards the end, Starscream finally decides to defy Galvatron and actually almost mamnages to beat him in a fight despite Galvatron having the Star Saber. In the end, however, Starscream is impaled, but with his last breath, gives Unicron an almighty blast. End result? Sideways gets the Star Saber, and Starscream's final attack dissipates long before reaching Unicron.
Starscream's futile attack and Unicron's response do finally convince Galvatron that Unicron is a real threat. The resulting Enemy Mine with the Autobots leads to Unicron's defeat.
In Legend of Galactic Heroes,both Blumehart and Patorichev die trying to protect Yang Wen-Li. Despite their efforts, Yang is shot and bleeds out before help arrives.
In Fairy Tail, legendary ice mage Ur sacrifices her life (sort of) to seal the demon Deliora in unbreakable, unmeltable ice for eternity. Since Deliora was a rampaging beast of destruction, that seems awfully noble of her—until you recall that the reason she did this was to snap one of her two pupils out of his Revenge Before Reason obsession. It worked—only for the other pupil to head down a similarly destructive path after her sacrifice.
Many, many chapters later, it actually helps out. Ultear, her true daughter, finds out that her mother has become one with the ice and can reconcile with her due to being separated for genetic experiments and the scientists lying to Ur's face that her daughter was dead.
In One Piece this is performed by the elite guards of Arabasta who drank the hero water (a drink that makes you incredible powerful at cost of killing you in 5 minutes) just to save the princess from the Big Bad. He just stood on the rooftop of palace and waited until they died, unwilling to fight against them just because they did it.
A non-lethal, comical variant, where if Luffy fell into the water, Chopper, followed by Brook, would jump in to rescue him, forgetting that they are also Devil Fruit users and cannot swim either. Zoro or another crewmate usually saves them each time.
In the second episode of Code Geass R2, Urabe self-destructs his Knightmare Frame in order to defeat the seemingly-invincible opponent Knightmare (or, at the very least, to buy time for Zero and Kallen to get away from it). Unfortunately, Urabe had no way of knowing that his opponent possessed a power which lets him (subjectively) stop time, allowing him to avoid the brunt of the explosion.
During the Eclipse in Berserk, both Pippin and Judeau make Heroic Sacrifices to save Casca from getting killed and eaten by the ravening demons after Griffith marks them and everyone else with the Brand of Sacrifice. While Casca does escape a Cruel and Unusual Death at the hands of the demons, she ends up suffering an equallyhorrificordeal at the hands of the newly-incarnated Femto that ultimately results in her losing her mind (as well as having the child that she made with Guts prior to the Eclipse corrupted by Femto's rape) despite Guts' best efforts to save her.
Almost happened in the first episode of Bleach, where Ichigo tries to sacrifice himself to save his family from the Hollow. Rukia calls him an idiot, as the Hollow would have eaten everybody else after eating Ichigo.
Later, Yamamoto pulls one of these by using his zanpakuto's flames to basically nuke the Fake Karakura Town with Aizen in it, sacrificing his life (and the lives of all his subordinates) in the process. However, Aizen predicted this, and gave Wonderweiss the ability to nullify Yamamoto's flames, making his attack pointless.
In Puella Magi Madoka Magica, Kyoko sacrifices herself so that Sayaka, who had transformed into the witch Oktavia von Seckendorff, would not die alone. The original plan was to try and get Sayaka to revert back to herself by using Madoka, her best friend. They quickly find out that no, Sayaka isn't in that monster and starts attacking them. Kyoko sacrifices herself so that Madoka and Homura can escape. We later find out that this was all just an incredibly cold and heartless plan set in motion by Kyubey, who made Kyoko believe that Sayaka could be saved (which, in actuality, was hopeless). Now that all of the other magical girls are dead, Homura is the only one who can fight Walpurgis Night, the ultimate witch who cannot be defeated by a single magical girl. And so now, what will Madoka have to do that Homura has been trying to prevent the whole series in order to save her home? Become a magical girl, of course.
In Naruto Sarutobi Hiruzen sacrificed his soul to stop then-current Big Bad Orochimaru. While this did bring his immediate plans to a halt, it didn't actually do anything to hinder Orochimaru in the long run, apart from forcing him to switch bodies before Sasuke could arrive at his base, and even if he had succeeded it's been established that he can completely resurrect from any of his subordinates' cursed seals, so basically Hiruzen killed himself to kill Orochimaru and utterly failed in every respect. Taken even further in a later chapter when Orochimaru cuts open the death god freeing the Hokages' souls and his arms, restoring his ability to perform jutsu. Hiruzen even complains that his sacrifice was rendered useless.
Subverted in that while it didn't do anything to stop Orochimaru, it did have the unintended benefit of preventing Kabuto from reviving the other three Hokages to use in the war, which would have made things WAAAY more difficult for Team Good Guy.
Deconstructed in Attack on Titan. While the story acknowledges that sometimes one person's death can save many lives, it also tears into the idea of self-sacrifice as ennobling someone at all. There is no such thing as a dignified death (because being eaten by a Titan is an utterly nightmarish way to die), and anyone who tries to sacrifice themselves for the sake of others gets quickly outed as a narcissistic wastrel: essentially, they want to be remembered as brave heroes while taking the coward's way out.
A rare inversion occurs in chapter 50 where Hannes protects Eren and Mikasa and dies in the process, but his death is the main catalyst for the activation of Eren's new power.
In Transformers: Last Stand of the Wreckers, Pyro decides to forgo his dreams of sacrificing his life for some epic cause to hold off some pursuing Decepticons. He doesn't even get in a shot before they tear him apart.
There was an X-Men story somewhere, where a civilian scientist takes an energy blast meant for Bishop and dies, completely unaware of Bishop's Energy Absorption power. The action does help improve human/mutant relations, though.
One issue of Marvel's G.I. Joe series had Scrap Iron fire a missile at a wrecked car with people inside. The Soft Master (who was trying to save the trapped people) intercepts the missile and gets blown up himself. Unfortunately, Scrap Iron has a second missile which he uses.
In Star Wars, a group of Jedi lure Darth Vader into a trap and try to kill him, and he effortlessly annihilates them. When it finally gets down to the last three Jedi, they manage to cripple him, but just as they are moving in for the kill a squad of 501st clone soldiers arrives and rains fire down on them, killing one. Tsui Choi, one of the Jedi masters, selflessly lunges at the clones in order to buy the other Jedi time to escape...but Vader seizes him in midair with the Force, pinning him helplessly in the sights of the clones, and both Jedi die.
In The Secret History, Aker tries to destroy William de Lecce but only succeeds in killing herself. She's the first Archon to die, so we don't know if she'll actually stay dead or not. Erlin certainly thinks she's dead.
In Sonic the Hedgehog, Tobor, a former Guardian who was replaced by a member of the Dark Legion, finally reemerges from the zone he and former DL leader Kragog were trapped in and find Angel Island being ready to be fired on by a massive ship. Tobor decides the only way to solve things is to take Kragog and slam the both of them into the cannon, destroying it. Pity he had no idea that the weapon was being used to restore other trapped Echidnas on Knuckles' orders, forcing the powered up Guardian to become a Reality Warper.
In the Magical Girl Lyrical Nanoha/Sailor Moon crossover fic White Devil Of The Moon, the Sailor Senshi believed that Princess Serenity was this noble figure, someone to look up to as a champion of Love and Justice and that the Senshi and Endymion's sacrifices got her as far as possible before the Dark Kingdom killed her. Then, her reincarnation, Nanoha Takamachi, reveals that she did no such thing - when Endymion was slain, Serenity took Venus' sword and stabbed herself with it.
A Growing Affection: Karin's death qualifies. She died fighting Kisame so he could not interfere with Sasuke's fight with Itachi. Except Kisame would not have interfered in the first place, and would not have even attacked Sasuke in the event of Itachi's loss, because it would have gone against Itachi's wishes. Not to mention the effect her death had on Sasuke...
The film Gallipoli is based entirely around this trope.
The jihadists in Four Lions dream of making a grant Heroic Sacrifice (from their point of view, at least), but each one of them ends up throwing his life way in an utterly pointless fashion.
In the remake of Dawn of the Dead (2004), a good portion of the survivors suffer this in the film's finale. They drive across the devastated city, aiming to reach the local marina and use one of the survivors' yacht to sail to an island out in the Great Lakes, where the zombie swarms can't possibly reach them. After said sacrificing, the last handful escapes on the boat, but as they dock on the island, they are greeted by dozens more zombies. Even if they manage to get back onto the boat (we don't actually find out; it's a Bolivian Army Ending), they probably don't have had enough fuel to go anywhere else.
Defiance sees one of the non-combatant Jews rush a group of German soldiers with a live grenade, only to be shot a few yards into his charge and for his grenade to blow up by his body.
In Pirates of the Caribbean: Dead Man's Chest, Will bets his soul for the key to the titular chest in a game of Liar's Dice against Davy Jones. When it looks like Will is going to lose, Will's father makes an absurdly high bet so that Jones calls him out instead (at the same cost). Though noble, this turns out to have been a bad idea for two reasons. One, Will didn't care whether he won or lost, the main goal of the game was to trick Jones into revealing where he hid the key. Two, though this is never addressed in the film itself, observant viewers will notice that Jones had five fives and Will had three. Will had bet eight fives, which means that if Bootstrap hadn't intervened and Jones had called him out instead, Will would have won.
OTOH, had he lost, Will would have been bound to Davy Jones's will, which could have buggered the plot anyway.
In Letters from Iwo Jima, various Japanese soldiers start killing themselves after their first defensive position was about to be overrun despite the fact that their commanding officers told specifically not to do that and instead fall back to continue fighting.
Played straight in Animorphs. In a mission to capture the Pool Ship in order to use its communications systems, it's evident that a split faction, led by Tom, is planning to kill everyone involved and make their escape using the Blade Ship. Jake orders Rachel to infiltrate and disable the Blade ship, and though she knocks out the weapons systems before finally succumbing in a six-to-one fight. Unfortunately, Erek drains the Pool ship's weapons systems, so rather than having its engines knocked out, the Blade ship escapes anyways, though Tom is killed.
Subverted in C. S. Lewis' Chronicles of Narnia. In The Lion, The Witch and the Wardrobe, Aslan (Who else?) agreed to give up his own life to Jadis in order to save Edmund. Before killing Aslan, Jadis tells him that she's still going to kill Edmund (and everyone else in the rebel camp). Later, Aslan resurrects himself (invoking a loophole in the Deep Magic) and proceeds to kick Jadis' butt.
In Harry Harrison's novel The Daleth Effect, Denmark's space liner is invaded by US and USSR agents in an attempt to steal the piece of Applied Phlebotinum allowing the ship to fly. In response, the captain of the ship triumphantly tell both parties that all their efforts are in vain, as a fail-safe has been installed on board to prevent a takeover. The ship is destroyed seconds later. The captain's widow laments that all the crewmembers and passengers, including the inventor of the device, died in vain to protect a secret that was already made public days before. Even worse, since Denmark refused to patent the technology for fear of it being misused, they now have nothing.
It's even worse for the widow (who is American and has never applied for Danish citizenship), since she's partly responsible for the Americans being able to board the ship. Earlier, she is approached by an American agent, asking her help in obtaining the plans of the Anti Gravity device, threatening to revoke her American passport if she won't help. She refuses, but later discovers that her husband is cheating on her with a stewardess. In a fit of rage, she steals the inventor's notebook and gives it to the agent. He reveals that it's just the plans for a portable fusion reactor, which they have no interest in stealing (they'll just buy the patent and avoid legal trouble). However, he uses the notebook to blackmail her into spying for them.
In Only In Death, Rawne orders his officers to tell the Ghosts that if they slip up, Gaunt's death will have been in vain.
In Necropolis, one of the Vervun infantry commanders grabs as many explosives as he can carry and charges towards a Chaos war machine. He makes most of the distance without the guns touching him, but is shot down - but when the war machine runs over his corpse, the explosives detonate and ruin it. Not to mention the entire book, from the first tankers to the fighting in the Spike, given that Vervunhive is official disbanded at the end because of the massive casualties.
I think that falls under a different trope. The point of the battle was largely to deny Chaos the world. But on a more personal level, it was a chance for the Ghosts of Tanith to fight the battle Gaunt denied them when he fled Tanith. And it is arguably the only thing that allowed the Ghosts to survive as a unit since a large portion of the Vervunhivers they fought with would later join the Ghosts.
Subverted example in Harry Potter and the Half-Blood Prince. Dumbledore's expedition to retrieve a horcrux from Voldemort's trap-filled cave ends up getting him killed in the attack on Hogwarts, and it turns out the horcrux was already gone. Except it's later revealed he was already dying anyway, and it probably kept Harry from getting killed going in there alone, as well as providing a way for Snape to kill him.
RAB is a straight example. Actually, he made the horcrux harder for Harry to find and destroy (because he handed it to Kreacher hopping he would be able to destroy it). Can even be considered Stupid Sacrifice when you think what could have been if he told Dumbledore everything he knew instead.
Katniss volunteering for The Hunger Games to probably die in place of her sister Prim proves senseless because Prim dies in book three, as a direct result of the rebellion Katniss inadvertently kicked off. The same rebellion kills lots of other people, and ends up putting in place a government no better than the one they toppled, which Katniss then has to take down, leaving the whole situation up in the air. It's also arguable whether Katniss actually did the rebellion any good as the mockingjay, since her participation was pretty limited.
Subverted in Brandon Sanderson's Mistborn. Kelsier challenges the Lord Ruler and is killed in what appears to be a Senseless Sacrifice. Later, it turns out that this was all part of the plan, and his sacrifice is what finally inspires the people to rise in rebellion.
In Neverwhere the Marquis de Carabas allows himself to be killed by the resident Two Bad Guys, Croup and Vandemar in order that he may learn something of the nature of their employer and purpose. As it happens, he has his life hidden away somewhere else so that he can come back, so this is less a sacrifice than it might be; however, it is utterly unnecessary, as by the time he gets back to the other characters, they already know who the Big Bad is.
In The Saga of Darren Shan, Mr. Crepsley goes out with one of these when he tackles the Vampaneze Lord during a one-on-one fight, sending them both into a spike pit below. Of course, the real Vampaneze Lord wasn't the guy he fought. It's Steve - the main character's childhood friend.
Longtail in Warrior Cats gives his life in Fading Echoes to save.......... a half-eaten mouse. And it doesn't get saved.
Maester Cressen in A Song of Ice and Fire. Stannis Baratheon's Old Retainer, he sees Melisandre of Asshai as an Evil Chancellor who's tempting his beloved master into a heretical religion and influencing him to do evil things in the pursuit of power. The only way he can think to get rid of her is to offer her a toast from a poisoned chalice, despite knowing that etiquette will require that they both drink. They do; and as an early indicator of how truly powerful her god is, she survives the poison unscathed while he dies on the spot.
In Earth Strike by Ian Douglas, a Turusch fleet arrives to the Solar System in order to attack Earth and Mars. The High Guard, a sub-fleet of the Space Navy whose primary task is to monitor and prevent Colony Drops with payloads of fusion bombs, detects the Turusch fleet arrival and destruction of the Triton monitoring base. Several High Guard ships send a message to the Navy and proceed to intercept the enemy in order to provide intel for the main Confederate fleet. The entire group is destroyed in short order (especially since the High Guard is composed of old ships stripped of their weapons)... after one of the Navy admirals already figures out that the Turusch fleet at Triton is only a distraction.
Live Action TV
In Captain Power and the Soldiers of the Future, the Icarus space station is dropped out of orbit and set on a course for Volcania. Lord Dread commands the Biodread, Soaron, to intercept, by telling him that the station will destroy "the Home of the Machines: your home." Soaron goes, knowing very well that he has absolutely no chance to stop the impact of millions of tons of flaming steel. He still flies into its path and screams his name in defiance before being destroyed.
He would have come back for sure though as he was being set up for a Heel-Face Turn in the next season if it had gotten made.
Of course, for Charlie it makes sense: he clearly knows he's going to die and embraces it the entire episode.
Inverted, in a way, the Torchwood miniseries Children of Earth. John Frobisher kills his children in order to keep them from being turned over to the 456, then kills his wife and himself, presumably to spare both of them a life without their children. This was unnecessary not because he failed, but because the 456 are defeated before they take the children, and he could have helped achieve this if he'd been willing to work with Torchwood. Not a Stupid Sacrifice because his motivation makes sense. It seemed almost inevitable that even this would go terribly wrong, as not one good thing happens to him in the entire miniseries.
Also, Ianto's death seemed to pretty much come under this trope too.
Subverted in Doctor Who. For the first four seasons, we are led to believe that the conclusion of the Time War was a Senseless Sacrifice for the Time Lords; the Doctor sacrificed his own people to wipe out the Daleks, but a handful of Daleks survived. However, in The End of Time, it turns out that the Doctor's main target was the Time Lords themselves, who had been so corrupted by endless warfare that they were about to destroy the entire universe in pursuit of victory.
Also, he had pretty explicitly stated before that he didn't much care to go on living after Fred's death.
The Supernatural episode "Abandon All Hope" includes a heartbreaking death for Ellen and Jo in order to make possible an attempt to kill Lucifer with the Colt. It fails.
In another episode foreshadowing these events, Dean is sent to the future by Zachariah to meet his future self after turning down Michael. Future-Dean turns out to have become such a hate-filled, heartless bastard, that he gets many of his present good friends killed just to get close to now Lucifer-inhabited-Sam with the Colt. Apparently he doesn't even get the chance to shoot the gun before he's killed, making Cas and the others' death completely pointless, even for the present-Dean, who doesn't understand that even if he got a shot, it still wouldn't do no good. Then the Ellen/Jo thing happens.
To be fair, Ellen and Jo did assure Sam and Dean's escape from there. On the other hand, if they did die (and they did a lot), they'd just be brought back.
Rio in the penultimate episode of Gekiranger thrusts himself into the Big Bad and pretty much self destructs. Though it's revealed not two minutes later that the villain survived it.
In the scene where Donovan arranges to trade himself for his son, the rebels are set up to ambush the visitors, but they don't. Instead, they let Donovan get taken by the aliens.
In a scene where the rebels are sabotaging the water facility, one of the rebels is wounded. The rebel's girlfriend comes back for him and insists she will stay with him. Two (fit) mercenaries come back, too. They pick up the perfectly fit woman and haul her away, leaving the wounded man behind to be killed. If they'd grabbed the wounded man instead, they would have all made it out alive.
In the finale of Power Rangers Turbo, T.J. decides to activate the Rescue Megazord's self destruct in a last resort to destroy the enemy (granted the Megazord was horrendously damaged and they didn't have time to repair it on the battlefield). The monster survives, requiring the Rangers to switch to the Turbo Megazord... which also gets defeated. They do eventually beat the monster, but later the Command Center is destroyed and they lose their powers.
A similar thing happened in the source series Gekisou Sentai Carranger, in the exact same footage, the enemy survives VRV Robo's self-destruct, RV Robo gets badly damaged (but is later rebuilt) and the monster (who is the Big Bad, Demoted to Extra in Power Rangers), only dies after being shrunk by stale Make My Monster Grow food (changed to a weapon sacrifice in Power Rangers since the Make My Monster Grow method was changed).
In Power Rangers in Space former Big Bad Astronema turned traitor but is sent back to her old base in order to stop an asteroid from hitting Earth. It doesn't work. Overlaps with Stupid Sacrifice because the Rangers had Megazords they could have used. (Granted, Astronema did volunteer and the Megazords they had weren't enough anyway, they needed one more)
On Robin Hood, Marian prevents Guy of Gisborne from assassinating King Richard at the cost of her own life. However, if one knows their history, it's rather depressing to realize that Richard returns to England only to leave and then die soon after in Normandy.
Al on Flash Forward commits suicide because his flash forward has him receive news on the death of a woman. Afterwards, everyone takes to the fact that the flash forwards will not necessarily come true. In a later episode, the woman is hit by a car and dies anyway. Al was only receiving the news of her death and was not responsible for it.
Dr. Janet Fraiser's death in "Heroes, Part 2" was viewed as this In-Universe by the SGC's watchdog organizations. She saved the man she was treating, but as he was a Red Shirt and she the SGC's chief medical officer, it was not viewed as worth it.
Col. Lionel Pendergast went down with the SGC cruiser Prometheus in "Ethon," trading his life to beam his surviving crew off the ship. Arguably turned into this by the episode's Shoot the Shaggy Dog ending: the SGC did not complete its mission and lost a ship and at least 39 crew in the process.
Called a "phantom sacrifice" in Bridge. A team bids a contract expecting to go down (the sacrifice) to lose less than they would defending the opponents' contract. Unfortunately, the opponents' contract doesn't make.
In Yu-Gi-Oh!, monsters above level 4 need monsters to be offered as a tribute to be able to summon them, requiring you to sacrifice them and send them to the grave. This becomes a waste cost if your opponent negates the summon with a Trap Card or Monster Effect - you lose the tributed monster and the summoned monster.
Anatoly's return to the USSR at the end of Chess; he does it primarily so Florence can be reunited with her father, but afterwards Florence finds out that her father is probably dead after all.
Parodied, like every other WWII cliché, in the "Aftermyth of War" sketch from Beyond the Fringe.
Peter Cook: Perkins, I want you to lay down your life. We need a futile gesture at this stage. It will raise the whole tone of the war.
In the opera Il trovatore, Leonora, desperate to do anything to save Manrico from execution, marries the Count di Luna and takes a poison that will allow her to live just long enough to break him out of dungeon. But Manrico is so shocked to discover his lover's infidelity that he refuses to make his escape. The Count watches Leonora die and has Manrico executed at once.
One could easily argue that the end of Shakespeare's Romeo and Juliet has a potential double helping. Romeo, believing Juliet dead after her Fake Death, offs himself with a poison. While it wouldn't have accomplished anything, Juliet's is more fitting to it. Not only did her "Fake sacrifice" Fail senselessly, it causes her to make a real one that accomplishes nothing at all. The only reason this counts is because her fake sacrifice is what forces her to make her real one, and Senselessly End It All.
In The Consul, Magda finally gives up waiting on the Secretary to get her out of her desperate situation, and leaves a note with Assan that she says "will convince John that there is no more reason for him to come back." Unfortunately, John does come back that very night to the consulate, where he is arrested. The Secretary promises to phone Magda, but calls too late.
This plays with the trope however, as while he fails to kill Golbez, he does weaken him enough to free your mind controlled ally Kain so he can join you again. Oh wait, Kain is still under control, Golbez was just faking it. It was senseless after all.
Even worse since Tellah is the only character in the game to sacrifice himself and actually stay dead. Not only does everybody else who attempts a Heroic Sacrifice pull it off successfully, they're able to stay alive no matter how impossible that should be.
Not really sure it's that senseless, if he hadn't done that Golbez would have probably killed all the party right there. The second time the party encounters Golbez, it takes a Big Damn Heroes moment from Rydia for them to survive.
For that matter, everyone who "dies". The most jarring example would be Palom and Porom turning themselves to stone to prevent walls from crushing you; the door in front of you could have easily been broken with a simple fire spell. Another involves Cid, who jumps off of an airship holding a nuclear weapon to seal the entrance to the underworld, when he could have just dropped it.
The Shofixti in Star Control 2 blew up their own sun in order to deal a crippling blow to the Ur-Quan invaders... which not only nearly wiped out their entire race, but caused the Ur-Quan (who sought to enslave all life other than their own) to lose their battle against the Kohr-Ah (who sought to destroy all life other than their own). Nice Job Breaking It, Hero.
Every time the monster Sin rears its ugly head in Final Fantasy X, a Summoner is sent on a quest for the Aeons in hopes of performing the Final Summoning that is said to be the only way to defeat Sin, a quest that invariably costs the Summoner his or her life. But as it's revealed, the Final Summoning does nothing to stop Sin for good, as the Final Aeon that destroys Sin becomes the new Sin, making everybody's sacrifices pretty much meaningless. Not surprisingly, Yuna in Final Fantasy X-2 rails against the entire idea of sacrificing one's life afterwards because of this, opposing a plan in which Nooj would shoot Baralai, who was under possession by Shujin, and then kill himself once Shujin re-entered his body because she has lost too many of her friends to sacrifice and doesn't want battles where "we have to lose in order to win."
Subverted with regards to Cid: Every opportunity he has to suggest it, he suggests a suicide ramming run using the airship. Every time, he's shot down as there's far less suicidal means of success. Rikku even mocks him for it one time.
Subverted in Metroid Fusion; in a cutscene, Samus pleads with the computer Adam to let her out to try to self-destruct the B.S.L. space station to destroy the X Parasites within (which would also destroy her, as apparently the ship's self-destruction would be immediate). Adam tells her that this would be pointless, as it would leave the X Parasites on the planet SR-388 (which the station was orbiting) alive and able to spread across the universe, while simultaneously destroying the universe's only hope to defeat the parasites, Samus herself. (He instead suggests setting the station to collide with the planet, destroying both along with the X Parasites and allowing Samus to escape before the station impacts.)
The engineer from Dead Space who cut off his limbs in an attempt to be unable to hurt anyone once he changed. Not only do you encounter a legless Necromorph that is apparently him, having died before finishing the task... but you later encounter necromorphs that hurt people just fine despite not having any of their original limbs, so even if he'd been entirely successful, it wouldn't have worked.
RuneScape has a few senseless sacrifices. For an example, in one quest, Turael, Duradel and a number of others try to attack a powerful Mahjarrat and most of them are toasted off.
Sonic 2006's Silver's quest ends with Blaze sacrificing herself to power the ritual to seal Eldritch Abomination Iblis away. It works... except they are in the future. Back in the present, Iblis is still alive and well and begins its plans to become invincible, forcing Silver to travel back and defeat Iblis then. Good job, Blaze.
MS Saga, a Gundam spinoff RPG, has Gavanger make a Senseless Sacrifice fairly early in the game by trying to hold off the Psyco Gundam on his own while the rest of the party escapes. The "senseless" part comes in when you realize that even the best MS you have available at the time wouldn't have been much more than a speed bump to Psyco Gundam. The situation is deliberately Gundam-Troperiffic, paying homage to the franchise's long and glorious history of similar sacrifices.
An odd example where this is part of the gameplay can be found in Pokémon. The moves Selfdestruct and Explosion do a lot of damage but render the user unconscious. This can be useful if you have other teammates, but if you have no other battle-ready Pokémon left on your team, it's an instant loss. Despite this, wild Pokémon will still use them for no apparently in-universe reason by spite (the real reason being that wild Pokémon have no AI and just choose attacks randomly).
That last bit may be at least somewhat justified. You would have to design believable AI for hundreds upon hundreds of creatures, each with any number of potential movesets.
Much worse is the fact that Team Rocket is fond of using Pokemon that know Self-Destruct. The Grunts often send out a single Koffing and immediately order it to Self-Destruct. If they're lucky, this will knock out one of the player's six Pokemon.
But what could possibly make the use of a move like Selfdestruct even more pointless, you ask? How about if they opposing Pokémon is ghost-type? Since Selfdestruct and Explosion are both normal-type moves they will completely fail to affect ghost type Pokémon, while still killing the user.
Perhaps even worse is a recently added move, "Memento". It will sharply decrease the target's Attack and Special Attack stats, but the user of said move faints. If a wild Pokémon uses this, it ends the battle, but...stat decreases and increases reset immediately after a battle ends.
A new move, Final Gambit, causes the user to faint and forces the opponent to take damage equal to the user's HP. It would already qualify for a Senseless Sacrifice by itself, but then you learn that Shedinja, a literal One-Hit-Point Wonder, can learn Final Gambit.
Modern Warfare has this in the "Shock And Awe" mission when your chopper crew stops to rescue a downed chopper pilot (in addition to the troops they were already rescuing.) The player shoots troops who have closed in on the chopper, drags the pilot out, carries her back to your chopper defenselessly...and then gets nuked. This is a point of debate between "If we had just completed our mission, we would have saved many more lives", and "No one gets left behind." That being said, even if they hadn't gone back for the pilot they still may have died in the nuclear explosion.
General Leo's attempt to kill Kefka in Final Fantasy VI achieves nothing at all besides his own demise. It's particularly jarring because he did it while all the main heroes were lying in the ground, knocked out, and yet they all survived.
Not such a huge waste - Kefka is called away by the Emperor immediately after killing Leo. He probably would have finished off the other heroes if Leo hadn't delayed him. Furthermore, Kefka obviously wants to kill Leo, with or without a fight. He even tells us the excuse he'll give the Emperor for doing it.
But played straight with Faldio. The whole point of his shooting Alicia (and thus ruining his career, and his life, and his relationship with his best friend) was to awaken her Valkyria powers so that she could save the entire Gallian military, which seems to work for the moment...but Alicia is too scared of her powers to try to save or lead them herself, and Selvaria blew up the entire army a few chapters later anyway.
And played totally straight with Selvaria. If she hadn't specifically requested that Squad 7 be the ones to escort the rest of her men away to spare them, they would have gotten burnt up like everybody else and Maximillian could have had Gallia in his pocket by dinnertime.
In the characters ending, Xianghua ofSoul Calibur does this in the fourth game, senselessly holding on to Kilik as he sacrifices himself to neutralize both Soul Edge and Soul Calibur. He was going to die, with nothing that could have been done without another characters interference, and there was no reason beyond suicidal devotion for Xianghua to go as well.What a Senseless Waste of Human Life...
Mortal Kombat: Deception starts out this way when a three-way showdown between Raiden, Shang Tsung, and Quan Chi is interrupted by the resurrection of the game's Big Bad The Dragon King. Both villians try their hand to take it out with their own sorcery to no avail, then try it together; again, to no effect. In a brief Crowning Moment of Awesome, Raiden gets up, and all three enemies join forces to try to destroy the Dragon King...unsuccessfully. In a last-ditch effort, Raiden uses the aura of all three of them to send a powerful Heroic Sacrifice magic explosion that kills them and destroys everything...everything except for the Dragon King, who now holds the amulet the three were fighting over that could reawaken the King's undead army.
One of the main plot points in Tales of Symphonia revolves around this. To save the world of Sylvarant from rotting away and dying, the chosen of regeneration has to go beyond simply giving up his/her life, they give up aspects of their humanity one by one beforehand. They give up their sense of touch, taste and ability to speak before finally giving their lives. It later turns out to be pointless because Sylverant exists parallel another world called Tethalla. The two worlds exist by vying for each others mana, essentially their lifeforce. The journey of regeneration reverses the flow from one world to the other, taken by the chosen one would prosper and one would decline...If the characters in the game did complete the journey of regeneration, it would only temporarily save their world, the cycle would continue. Ultimately, they manage to solve this by saving both worlds.
Inverted when it turns out that Hope wasn't any good at defeating Zeus because Kratos still didn't forgive himself over the death of his family. It takes the spirit of Pandora, during the moment Zeus is choking the life out of him, to get Kratos to forgive himself and gain the true power to kill Zeus.
Halo: Reach. Jorge sacrifices himself to detonate a slipspace bomb, destroying a Covenant Supercarrier. He dies believing that he'd saved Reach. Moments after his death, the main Covenant armada arrives at Reach, and the planet falls anyway.
That said he did just destroy a supercarrier and every covenant soldier on board, he may not have saved Reach but he did do the enemy a lot of damage.
In the comic version of Left 4 Dead, Zoey's father is attacked by his ex-wife/Zoey's mother, who is a zombie/infected. He gets bitten and being Genre Savvy, he assumes that he will start to turn and asks Zoey to shoot him in the head so that he won't become a zombie. 2 weeks later, Zoey is told by a military doctor that she and the other survivors are carriers of the virus that are making people zombies, which makes them immune from changing and the carrier gene is passed down from the father. Zoey goes into shock, realizing that sacrificing her father was completely pointless.
In Metroid: Other M, Adam went on to Sector Zero to destroy the supposedly unfreezeable Metroids and promptly activated the damage-activated self-destruct. It seemed like a good idea at the time... then you meet the Queen Metroid.
In Fallout: New Vegas we have the incredibly sad tale of Vault 11: after being locked inside the Vault, the residents are immediately informed that every so often, one of the residents must enter a chamber in the Vault to be killed otherwise the computer will kill everyone in the Vault. After a long and terrible history (including things like sexual blackmail, coercion and armed insurrection) the five remaining residents of the vault (of the original one thousand) finally decide to end this and refuse to sacrifice anyone else...prompting the computer to congratulate them in being "fine examples of humanity" and unlock the Vault door (the Vault, like every other except for a few control Vaults, was a sick social experiment). Out of those five people, four committed suicide, with the fate of the remaining survivor unknown.
double subverted Vegas was a prime target to become a total desolate wasteland however Mr. House rigged missile defense systems prevented such a fate. If Vault tech's predictions came true then everyone in the vault would end up dead or ghoulified like in vault 34.
In the world of Warhammer40000, it's well established that the Eldar are a thinly spread race, clinging to the barest semblance of galactic survival. They're known for instigating events that hurtle entire sub-sectors (groupings of a few to dozens of planets, each inhabited by billions of humans or more) to their doom in order to prolong the lives of a few hundred of their own. So, come Dawn of War, its expansions and sequels, it can pretty well be summed up that any Eldar force you take down is committing this trope, especially if they're working on an end result that would probably work out better in the end if they would just think about the fact that the "primitive humans" might actually win. To whit: the Farseer's entire plan in Dawn Of War 2.
With information gained from the Eldar campaign Retribution, the plan does make a little more sense. The Eldar's objective in the sector is the retrieval a soulstones within a craftworld that crashed on Typhon aeons ago. The Eldar don't give a damn about saving the sector, simply stalling the Tyranids long enough for the recovery, and the Męlée ŕ Trois they start was a good way of doing this. Without a prophecy telling them so, the idea of the Blood Raven actually defeating the Hive Fleet was acceptably unrealistic.
In Eternal Darkness, most of the chapters apparently end with this. It seems like a bunch of Shoot the Shaggy Dog stories, even the ending. That is until the third playthough. Mantorok the corpse god set up a 2000 year plan to defeat the other 3 gods, but it had to be done in three parallel realities. So when the player beats the game for the third time, it is revealed that with each god weakened in one timeline, it's rival can kill it, but because all 3 are weakened, they kill each other simultaneously!
James, aka the Lone Wanderer's father. When the Enclave show up to take over Project Purity, he floods the control centre with radiation to kill Colonel Autumn and a few Enclave soldiers you were likely powerful enough to kill for him and kills himself in the process. Colonel Autumn survives by injecting himself with some kind of radiation protection, so it was all for nothing.
The Lone Wanderer or Sarah Lyons in the orignal ending. Someone has to activate the water purifier and if a human goes in, they will die from the radiation. You most likely have Charon, Fawkes or RL-3, all of whch are immune to radiation and are capable of entering the code...but the game doesn't let you send them in. Averted by Broken Steel, thankfully, unless you send Sarah in.
Kenny's death at the tail end of The Walking Dead game. Basically, Kenny, Ben, and Lee are trapped in an alley being closed in by zombies. Ben is impaled on a spike after he fell, and Kenny, with one one bullet left, pushes Lee into another corridor and shuts the gate before giving Ben a Mercy Kill and dying while he fights off the zombie horde. He didn't have to die. All he had to do was simply shoot Ben and go into the corridor with Lee.
Asura's Wrath: This is actually a pivotal element of the entire game. The Seven Deities have been killing innocents to harvest their souls for the sake of using the Ultimate Wave Motion Gun on Vlitra. Except that Olga ends up using the weapon on Asura, which only pisses him off and wastes the sacrifice of trillions of people killed over thousands of years. And then it turns out that Asura himself has the furious punching power to take down Vlitra himself. The fact that so many died for absolutely nothing is instrumental to Yasha turning against the rest of the Seven and aiding Asura in taking them down. And then it is revealed that the entire war with Vlitra was completely pointless because Chakravartin, the omnipotent evil, jackass god created Vlitra as a "test" to see who would become the next ruler of Gaia. Needless to say, when Asura learns of this and how all these deaths were just some asshole deity's succession game, he is pissed.
Whether these occur in the Mass Effect universe are largely up to the player's actions (or lack thereof), but one moment in the third game takes the proverbial cake. The conflict between the quarians and the geth has come to a head, and if you lack the resources or drive to bring them to a peaceful coexistence, you must choose one race or the other, with the one not chosen being utterly annihilated. At game's end, if you pick the "Destroy" ending, all synthetic life is wiped out. So if you side with the geth and then pick "Destroy", congratulations, you just committed pointless genocide on two sentient species.
A canonical-in-all-stories example seemingly occurs with the movie Paragon Lost, which details James Vega's life prior to joining the Normandy. During a Collector attack on Fehl Prime, he is faced with a difficult decision: he has gathered some extremely useful intelligence on the Collectors, which will be instrumental in the Alliance counterattacking them, but to secure it, he has to sacrifice all of the colonists of Fehl Prime, whom he has gotten to know over the past two years. He makes the call and saves the intel, but... Shepard goes ahead and blows up the Collector Base soon after anyway, but Retaliation reveals that there were more Collectors than simply the ones in the galactic core - so the intelligence (especially the seeker sting antidote, which saves many operatives withequal combat capabilities to Shepard's from seeker swarms, turning them from instant paralysis to a simple power cooldown debuff) was useful after all.
The death of Admiral Zaal'Koris in Mass Effect 3 is potentially this: if you do not save him he sacrifices himself to save the lives of his civilian crew, but depending on other factors, his death can make it impossible to make peace between the quarians and the geth, thus potentially leading to the extinction of his entire species - including the ones he died to protect.
Tsukihime: Arcueid vs. Roa in her route. Judging from the epilogues, it's clear she didn't expect to survive the battle considering how hard she had to fight off her bloodlust when she overdrew her power to use her Marble Phantasm for what is actually a rather minor effect. It motivates Shiki enough to give Roa a "World of Cardboard" Speech, kill the hallway and then kill him. She gets better, though, in the Good Ending. The True End she still gets better, but because she overexerted herself she can no longer control herself and decides to just sleep for the rest of eternity.
Rann of Drowtales attempted to kill Snadhya'rune to avenge Diva'ratrika. This fails when his target's summons succeed in overpowering him. In a last ditch effort he uses an explosive mana core to to create a large explosion that kills him, but leaves Snadhya'rune with barely a hair out of place.
Hilda in the webcomic Fans!, captured by an enemy order, telekinetically prevents her automaton double from shooting Rikk by making it shoot itself instead. Her captor informs her that this was his plan all along, in order to demoralize her organization.
Earlier in Fans!, Harry attempts a human bomb attack on General Maximillianna with a handheld phaser on overload, only to have the attempt fail because she was warned by his battle cry of "sic semper tyranis!".
In The Order of the Stick prequel book Start of Darkness, the original bearer of the Crimson Mantle tried to sacrifice himself to stop the crusading Paladins from destroying the goblin village. They easily killed him, then went on to slaughter the rest of the village.
This trope is important to the end of the story as well. Redcloak's brother Righteye is determined to destroy Xykon at all costs, but Redcloak believes he will be necessary to helping the goblin race. Righteye flies off to attack Xykon (who is distracted while fighting a powerful Archmage) with a magic knife that will allow him to Sneak Attack the lich for Massive Damage. Redcloak chooses to kill his own brother to protect Xykon...who then reveals that he knew about the knife all along and was immune to its effects. Redcloak murdered his sibling for nothing, and now Xykon knows that he will never betray him or it would make his loss even more pointless.
Played hard in Goblins due to Kore's cunning. Chief attempted to delay him so the others could escape, but the paladin, recognizing the plan, incapacitated Chief before slowly and methodically torturing the poor goblin, using the screams of agony to lure the others back.
And once they're lured back, we get another Senseless Sacrifice because Chief dies from his wounds from the torture. Moral victory?
A second example: Dies-Horribly accepts a Deal with the Devil, trading his soul to the demon who guards the Orb of bloodlight so that Duv can have the orb and no more of her slaves will need to suffer. Turns out, the Demon's promise relied on Exact Words, and all he gets for his soul is a worthless ball of blue stone. At least he got his soul and life back after the demon realized that Die's arm had a soul of it's own, thus meaning it had breached their contract
Wapsi SquareBack Story: Jin's suicide did not derail the spell as she hoped it would. It did have a significant effect eventually, but much, much later than she wanted.
Played for comedy in Dr. McNinja when the mayor of Cumberland makes a deal with a demon samurai ghost thing: his soul in exchange for the demon abandoning a plan to raise an undead army. Immediately after the demon leaves, a man runs up to the mayor asking if he'd seen it, then saying that he was of a bloodline that could stop the demon and that it would have been ludicrously easy for him to banish it for another hundred years.
Almost happened in Sapphire Episode III. Even after Boris killed Ivanka after promising Alec would be spared, he proceeds to kill Alec as well. He is saved, however, when his friend Andrew pulls a little Deus ex Machina.
Parodied in the web animation Ducktale Z 3 when Huey martyrs himself in an attempt to stop Vegeta, likely homaging Chiaotzu's death against Nappa in DBZ:
Louie: I'll miss Huey.
Dewey: If only he hadn't blown himself up when I had a perfectly good rocket launcher right here!
Jon: Alright, who's sacrificing their life? (Josh walks off the edge and misses completely.) Josh: DAAAGGH! (Laughter) Jon: Okay, you can do it, Josh!
The former page quote comes from Shadow Raiders, a rather grim kids show. By episode 20 the Beast had already eaten three inhabited planetson screen, two of them belonging to the protagonists! While the inhabitants of planet Fire managed to evacuate, the not evil at all vizier crashed the planet into the Beast to no effect. Planet Jungle chose to sacrifice itself since it could not escape, and again did no visible damage.
And then, in the Grand Finale, the Beast is teleported away from Planet Rock at the last second by driving the Prison Planet into its maw and having its World Engine take them both to the far reaches of the galaxy. The last scene of the series, after all the triumphant cheering and congratulating, is of the Beast devouring another inhabited planet, with the heavy implication that it has assimilated the Prison Planet's teleportation technology.
Let's not forget Planet Water, which the entire planet was turned into one massive cannon putting everything it had in one shot (which killed everyone on it), doesn't even dent the Beast.
The death of Jet and the at the time assumed deaths of Smellerbee and Longshot are this in Avatar The Last Airbender, they never found Appa in the HQ which was what Jet's sacrifice was meant to do, buy them time. Not to mention the Dai Li aren't taken down either.
Sadly, in The Legend Of Korra, Lin's sacrifice (she's not killed, but her bending is taken away) for Tenzin and his family becomes this when it's revealed that they're all captured anyway.
The Princess and the Frog has a rather big one, though caused by Fridge Logic. Ray didn't really delay the shadows more than seconds, they were still around for the big confrontation, just not doing anything. Still effective, and awesome.
In Gargoyles, Macbeth had a Senseless Sacrifice in his flashbacks; after he was officially killed by Canmore and his son Luach took his crown, he realized that Luach's only hope of defeating Canmore was if Macbeth himself remained officially dead. The end result:
Phoebe: Did your own death save your son Luach from Canmore? Macbeth: No.
In the second season finale of Transformers Prime, when the Decepticons launch a full-scale assault on the Autobot base, Optimus orders the humans and other 'Bots to evacuate through the GroundBridge, while he stays behind to destroy the controls so that the 'Cons can't come after them. However, what makes this senseless is the fact that moments later, Megatron uses the Nemesis' Wave Motion Gun to obliterate the entire mountain, destroying not just the Bridge, but seemingly Optimus in the process.