A staple way of killing off minor bad guys in action films. Especially after they do something stupid, like picking up a live grenade.
In Reno 911!: Miami, The Rock gets overconfident with his grenade handling and ends up turning himself into red paste.
Subverted in Battlefield Earth, as while Big (Dumb) Bad Terl has an explosive collar strapped to his arm when he triggers the detonator that he believes will kill the hero's love interest, he doesn't die from it.
In The Producers, Franz Liebkind isn't sure whether he's used the slow fuse or the quick fuse when arming a bomb to blow up the building where he and Bialystock and Bloom are currently standing. So in order to test it, he lights it to find out. Turns out he was smart after all; he thought it was the quick fuse and so it was. ... Wait, Oh, Crap! An aversion in that nobody is killed, although Liebkind winds up in a full body cast.
Act of Valor. A female jihadist wearing an explosive vestblows herself up when the SEAL team bursts into the room she's in. Nearby is another suicide bomber; we get a Slow Motion shot of him turning toward the fireball, then suddenly going up himself as the blast detonates his own vest.
In Angry Video Game Nerd: The Movie, a non-lethal example occurs; General Dark Onward loses his right arm by fumbling his own grenade during his first encounter with the Nerd.
In the first season, which resulted in the death of Dr. Arzt, pictured above. This was especially jarring, since he had spent the previous minute handling the stick of unstable dynamite with extreme caution.
In the sixth season, when Ilana drops her bag containing dynamite on the ground and it explodes, instantly killing her. Ironically, this was just after lecturing the survivors about her ability to protect them.
Of course, after the fact it was decided that the immortal Richard should carry it.
In a one episode of Ghost Whisperer, a minor villain managed to kill himself after succeeding in exchanging a hostage for a special book, when his explosive device rolled off the table and onto the floor.
In an episode of NCIS, two criminals were trying to blow up a computer server to get rid of files... and ended up hitting a gas main, literally incinerating themselves in the blast.
An episode of CSI: Miami had some Western Terrorists planning to set off a dirty bomb in a helicopter using a bomb attached to an altimeter. In the cold opening a nervous looking man walks into an illegal rave and tells them to keep it down. Then explosions happen. It turns out he was experimenting in then next room when the impromptu party began and the vibration from the speakers in the next room set off a mercury switch (basically a very sensitive tilt switch) he'd attached to some explosives.
Played for laughs in Danish comedy series Finnsk Fjernsyn. In a skit about the Battle of Dybbřl in 1864, the hard-pressed Danish soldiers is issued a new revolutionary weapon: The hand grenade. The soldiers only instructions on how to use the explosive is "Pull out the pin, count to ten, and then stuff happens", upon which one of the soldiers takes out the pin, puts the grenade between his legs and starts counting...
In the 1000 Ways to Die episode "Tali-Bombed", a terrorists' bomb went off prematurely because they forgot to account for daylight savings time.
Played for laughs in The Red Green Show with explosives enthusiast Edgar Montrose. He's lost most of his hearing, several fingers and is permanently emitting a waft of smoke from his singed clothing. He claims he can fix anything with explosives, but even Red himself seems afraid of his methods, which says a lot about how Edgar embodies the spirit of this trope.
Played for laughs again on In Living Color! with Fire Marshall Bill, played by Jim Carrey. Bill's fire safety lectures would inevitably escalate into an explosive demolition of whatever building he was in, and possibly the occupants. Bill tended to survive.
The team on Criminal Minds point out the first victim of a bomb explosion is more often than not the culprit due to them being inexperienced with bombs.
Averted Trope: In The Outer Limits revival episode "From Within", a man with fetal alcohol syndrome needs to use explosives. No one else can, as he's the only one immune to the mind control worms due to his conditions. It doesn't help matters that his father died from misusing explosives. Needless to say, everyone but him is terrified he'll mess up. No, it all worked out.
Truth in Television
There have been cases of people blowing themselves up while experimenting with explosives in their own homes.
There are true stories of suicide bombers accidentally blowing themselves up only because their bombs went off too early. They deserved it.
A couple of Palestinian terrorists built a bomb with a timer while in their home, planning to make it go off in Israel. However, Daylight Savings Time was not observed at the exact same time in both places, meaning the bomb went off while it - and they - were still in the car. They won a Darwin Award right there.
There are stories of suicide bombers getting themselves killed when they gave their last goodbyes with a heartfelt hug to their comrades.
A Russian bomber died when his remote controlled bomb went off while he was transporting it to the Moscow airport. He had rigged a cell phone detonator and a telemarketer called him during transit.
A pair of terrorists once tried to blow up the Thomas Jefferson Cultural Center in Manila in 1991. They tried to set the bomb in the middle of the night, using a device rigged with a digital reader to count down the time. They armed it, but forgot what they set the time to. They check the time on the highly volatile explosives with a zippo lighter...but this is not what makes them fall under this trope. What makes them fall into this trope is that they set the bomb down upside down, and suddenly realized that when they set the bomb for five minutes they actually set it for five seconds. Surprisingly, one of the bombers actually survived and was caught in a local hospital.
Terrorists try to set up a roadside bomb, not knowing they're being watched by a helicopter gunship which is getting ready to blow them sky-high. Until the bomb blows up unintentionally. "Oh! Never mind", goes the Apache pilot.
Several of Guy Fawkes's Gunpowder Plot co-conspirators injured themselves with an accidental explosion while preparing for a daring last stand against the militia that had come to arrest them. During the chase, their personal supply of gunpowder (for their muskets and pistols) had been soaked by rain, rendering it unusable, so they spread it out in front of an open fire in hopes it would dry out more quickly.
How many of us remember the cautionary tale of what happened to Uncle X and the time he put a frozen turkey in a deep-fat fryer on Thanksgiving/Christmas Eve?
Another Darwin Award winner, an Iraqi terrorist, sent a mail bomb with insufficient postage and got it sent back to him.
In Northern Ireland, it wasn't unknown for an Irish terrorist to accidentally immolate himself with his own bomb. British security forces drily referred to this sort of incident as an own goal.
The Irish terrorists of the IRA and INLA were deeply paranoid organisations. It was not unknown for a member suspected of being a traitor or a security forces plant to be given a one-way assignment - told to place a car bomb, get out and return, the bomb would deliberately be on such a short fuse that it would dispose of the presumed security risk as well as the car.
"Grenade cooking" (see below), has a real-world referent. If retreating from a position on the Eastern Front, the Germans would deliberately leave behind a few suitably modified ready-use hand grenades. The Russians taking the position would see them, and if any Red Army troops could not resist the temptation to use German grenades on retreating German troops, would then discover they had a fuse time of maybe half a second between pulling the fuse and detonation...
Magic: The Gathering: Goblins are occasionally issued with explosives, which - given that a goblin genius is at best a barely functional human - rarely ends well for anyone, especially not the goblin. Goblin Kaboomist and Goblin Bangchuckers are among the less incompetent ordnance technicians, in that with toughness pump they have a chance to survive the injury they have a 50/50 chance of inflicting upon themselves.
This can happen in pretty much every First-Person Shooter game that features "grenade cooking" (waiting a few seconds before throwing a live grenade to give your enemy less time to run away or throw it back), if you hold the grenade for too long.
Not just those with cooking. Accurately throwing a grenade in a game that doesn't let you perceive the third dimension is much trickier than in real life (where it's not actually very easy to begin with), so it's easy to misjudge the distance and bounce the grenade on a nearby wall straight back into your face. If the game is Friendly Fireproof this merely results in embarrassment; if it isn't, well...
Not limited to the First-Person Shooter genre; anybody who's played a tactical or action RPG has probably done this too.
As a result of Artificial Stupidity, Mooks also frequently do this to themselves, and conversely, both your allies and enemies are often too stupid to take cover from the blast. Star Wars Battlefront has a particularly impressive line in it, with AI troops so enthusiastic with badly aimed grenade spam that it's not uncommon to get troopers listed as their own Nemesis, meaning they killed themselves more often than the other team did.
More than a couple of Demomen have blown themselves up with their own remote detonation Sticky Bombs by forgetting where they put them... or forgetting that while the unlockable Scottish Resistance usually requires them to look at the mines they wish to detonate, it will also trigger any that they happen to be standing near as well (originally meant to make the bomb jumping tactic easier).
It's also extremely common in single player when trying to set up chain reactions or blocking your only way out of a dead-end with a bomb. So common, in fact, that the game have a special Oh, Crap expression for the player character for when he's bombed himself into a corner.
Also common in Worms if one is careless. The lower AI levels sometimes even deliberately aim to hit themselves, frequently doing no damage to anyone else.
One of the cutscenes in Worms 2 has a worm try to blow up a rival by throwing a grenade at him, only to somehow throw the pin instead and keep hold of the grenade. He still has time to laugh, realise his error and then make an Oh, Crap expression before the eventual explosion.
Space Quest IV has an item simply labeled "unstable ordinance." Guess what happens if you pick it up and leave it in your inventory. Intelligence is actually rewarded with it, as if you take it you can then put it back where you found it and receive one Last Lousy Point.
Space Quest III makes you carry a thermal detonator, at one point. If you try to polevault with it in your inventory (long story), the predictable happens.
The ganados in Resident Evil 4 obviously haven't learned explosive safety, as they frequently frag themselves with dynamite or tripwire mines. As usual, Leon can also injure or kill himself with misthrown grenades or Exploding Barrels.
Tangos in Rainbow Six 3 sometimes, upon hearing your footsteps through a wall, proceed to throw a grenade at the wall and blow themselves up. Even better if there's a window they could have just shot you through.
There is also a part in one of the levels where an Exploding Barrel sits right behind a door. Use a breaching charge on it, and you can say goodbye to half of your team.
In The Revenge of Shinobi and Shinobi III, using the Mijin jutsu (a technique that heavily damages all enemies in the area and gives you another use of a jutsu of your choice at the expense of one of your lives) while you're on your last life will result in an automatic Game Over. To drive this point home, Joe's exploded body parts will simply fall off the screen instead of regenerating him.
Future Tactics subverts this beautifully. The first few levels feature enemy creatures that strap dynamite to their backs and explode when they get in range, damaging you but killing them. It's much later in the game that you learn the creatures have a machine that revives them if they die, so they can blow themselves up all they want and live to fight another day.
In F.E.A.R., it is not uncommon for Replicas to bounce grenades off walls back at themselves.
Red Dead Redemption contains a random encounter involving a couple of guys transporting TNT barrels. At some point, one the men mentions lighting a cigar while sitting on of said barrels. Players more intelligent than said character will take that as their cue to run the hell away.
In Bug Hunt, which is set on a space station, attempting to use the frag grenade as a normal weapon causes a Non-Standard Game Over. You can also blow yourself up by taking off on the shuttle after rigging it to explode.
In Schlock Mercenary, the demolitions expertlives up to his namesake. In his defense, somebody really did mess with his detonator and his eyes so that he would mess up the red button and the green one in an attempt to kill him while making it look like this trope.
A group of thugs try tossing an anti-matter grenade at Schlock only for it to bounce off a wall and explode at their feet. Or as Schlock prefers to put it, "They committed suicide when they saw me coming."
Pibald manages it again during the "Massively Parallel" arc by setting a mine that, thanks to a bit of poor planning, would go off when their employer - a robotic king built from a damaged tank - approached. While everyone concerned survived, the incident gave us the phrase "negligent regicide".
On Family Guy, Peter blows his fingers off before he finishes naming a firework
"I took 10 M80s and stuck 'em together, I call it Peter Griffin's Bunker Busting Mega Super Ultra"....*BOOM*
In American Dad!, Steve is planning on blowing up Roger with fireworks (don't worry, he's fireproof) because a hot girl said that she'd let Steve feel her breasts if he did something cool and dangerous. He lights "The Finger-Blaster" to start the pile, but it goes off in his hand, blowing off his thumb. The girl is still impressed, but his hand has been numbed by the paramedics when she makes good on her promise and she takes it the wrong way when he complains that he can't feel anything.