For their TV show, the Japanese band Arashi spent a great deal of time coming up with such stellar experiments as "How far can you sail a boat made of hay?", "Will wasabi still taste spicy if you hold your nose while eating it?" and "What happens if we have a hurdle race whilst wearing binoculars?" Unsurprisingly these all tended to backfire on them.
Radcliffe had moments of this as well, given his obsession with transhumanism. Lampshaded in "Let Me Stand Next To Your Fire" when he introduced AI android Aida to Agent May:
Fitz: Are you mad? Radcliffe: No, I'm just a scientist.
Leo Fitz also has shades of this within the Framework. He's built a fearsome reputation as a Hydra scientist, foregoing morals and ethics in favor of the progression of science and human experimentation.
Doctor Anthony Ivo from Arrow fits the bill, since he's on Lian Yu with the aim to seize and reproduce the Mirakuru Super Serum, and does unspeakable things in pursuit of his goals. He claims this is to save the human race. Later revelations make things a little more complicated; he actually wanted the Mirakuru to cure his wife of Alzheimer's disease, which drove him from a formerly upstanding doctor and scientist to the villain he is during the flashbacks.
Battlestar Galactica: Gaius Baltar is something of a deconstruction as his madness may or may not be messages from the gods, messages that ultimately give the key to finding Earth.
Phil and Lem from Better Off Ted took years to notice that "everything we do here is evil". And by extension, every scientist who works at Veridian Dynamics. Unusually for mad scientists they do stick to something close to proper scientific procedure.
Dr. Jack Hodgins, the "bug guy" on Bones, seems to think of himself this way. In "The Daredevil in the Mold" (Season 6, Episode 13, original airdate February 10, 2011), he tells his wife, forensic artist Angela Montenegro, "I've always wanted to be a mad scientist."
Walter White from Breaking Bad is arguably a rare example of this in a non-sci-fi show. He may not be the classical mad scientist, but he definitely owes something to the trope. He's apparently equally adept at organic chemistry, chemical engineering, mechanical engineering, and biochemistry, but the thing that really qualifies him is his willingness to use any or all of them to create drugs and kill people. It's made clear that Walt does have a sort of Freudian Excuse for his actions, feeling jealousy and insecurity over not using his scientific talents for anything great until now.
Apparently — according to David Fury when he questioned the incredible technological abilities of Sunnydale residents (reanimating the dead in 'Some Assembly Required', constructing lifelike robots in 'Ted' and ' I Was Made to Love You') Joss Whedon replied "You're just way overthinking it. The Hellmouth should be able to provide us with anything we want to do; the energy that comes out of it makes mad scientists out of humans who then go ahead and create something evil".
Even with the Slayer army, Andrew never stops experimenting with demon summoning and DNA, even breeding a dangerous demon back into existence.
Several episodes of El Chapulín Colorado deals with an invention from some kind of mad scientist, from a weakening potion to resurrecting the dead.
The Science Channel Dark Matters is all about Real Life examples who have popped up throughout history.
Doctor Who is filled with Mad Scientists, ranging from the slightly unhinged, endearing sort to the completely unrepentant, Omnicidal Maniacs.
The best example is, of course, Davros, the racist, maniacal and omnicidal creator of the Daleks, who easily conveyed just how twisted he was even without an Evil Laugh.
The Rani was exiled from Gallifrey when her pet lab mice grew gigantic and went on a rampage. They responded by letting her loose in the universe with a time machine. She took over at least one planet to experiment on the locals and drove them insane by removing their ability to sleep (which wasn't even the point). Thanks, Time Lords!
Most incarnations of the Doctor that don't just stick to adventuring. The Tenth Doctor's brand of mad science would easily have made him into a benevolent example of this if he weren't afflicted with too much Attention Deficit... Ooh, Shiny! to spend time on non-world-saving projects. And the Eleventh Doctor goes so far as to gleefully rock the steampunk goggles and shirtsleeves look while fiddling with the TARDIS.
Companions fall into this at times: Ace bordered on it, especially with explosives and practical chemistry. Adric may possibly have landed here too had he lived. Adam from the revival series also wasn't quite there during his travels with the Doctor, but was intended as the kind of young man who would end up as this.
Some other benevolent mad scientists include the resistance member in "The Dalek Invasion of Earth" who invented a chemical that could melt Dalek casings and sacrificed himself to test it.
Malohkeh from "The Hungry Earth"/"Cold Blood" certainly looks like one of these, but is actually a pretty reasonable person, reasonably sympathetic to the humans even if he does steal and dissect dead bodies.
The Syfy show Eureka, where the town's population is made up almost entirely of geniuses and scientists. The plots usually involve various degrees of scientific reality, from Real World, past theoretical, over possible but impractical, all the way to you gotta be kidding me.note Sometimes they stop at possible but impractical, but it's uncommon. Some problems (of planet-destroying proportions) are caused by a student's science experiment gone out of control. Suffice it to say that you gotta be careful when you ask a student to build a working model of the Solar system, unless you want a giant fusion fireball in the sky that won't go out.
Obviously, the title character in the Farscape episode "DNA Mad Scientist".
Walter Bishop,◊ most of whose nervous tics and general mental confusion disappeared about the same time he was released from the mental asylum (he claims that they were side effects of the drugs he was taking). He's still a "fringe scientist", which means he's focused on things like teleportation, astral projection, reanimation, and diseases-that-turn-skin-and-muscle-tissue-translucent.
Walter operates under the influence of up to a half-dozen home-brewed mind-altering substances of his own design. So if he seems less twitchy at any given time, it is because he is taking much better drugs than the generic crap he received in the mental asylum.
Interestingly, Walter's madness isn't confined to the crazy ideas he comes up with in his lab. It's also clear he just can't cope with everyday life without Peter (or Astrid) to take care of him and that he suffers as a result.
Except for the insanity part, most of the scientists on the show qualify.
Qyburn in Game of Thrones, the medieval version of this trope, as Qyuburn is a Maester, albeit a rogue one, accused of doing human experiments and "necromancy" (surgery).
Dr. Boris Balinkoff in the Gilligan's Island episode "The Friendly Physician", who performs mind-transfer experiments on the castaways. He also appeared in "Ring Around Gilligan", where he was testing his mind-control rings on the castaways.
Shocker, the terrorist organization from the original series has whole troops of these with an occasional Reluctant Mad Scientist among them. Their actions would mostly revolve around general terror and making people into brainwashed monsters. This has backfired twice, resulting in creation of Kamen Rider #1 and #2.
Dr Kiyoto Maki of Kamen Rider OOO is a brilliant but sociopathic scientist and one of the brightest in the Kougami Foundation, being in charge of its Biotech Laboratory, as well as the inventor of the Birth system. He's also an Omnicidal Maniac who wants to end the world and once locked several scientists in the lab with a Yummy that kills them simply because he wanted to see what would happen For Science!.
Ryoma Sengoku of Kamen Rider Gaim is sociopathic god wannabe, creator of the series' tech and lacks any sense and interest besides mad science and manipulating people. He really is the quirky Absent-Minded Professor he seems to be, but that doesn't stop him being complete bastard that used groups of teens as test subjects in his attempts to attain godhood. Emphasis on scientist as besides the god rants he is still more well adjusted than the examples bellow.
Kamen Rider Build is swimming in mad scientists due to its science theme. First there's Takumi Katsuragi, who created his own evil organization so he could use human experimentation to create both the Kamen Rider system and the Smash, and was noted by one of his allies for his ambition and madness. Nariaki Utsumi probably counts as well, especially apparent when he risks his own life for a dangerous experiment in the youtube special. And finally, while Sento Kiryuu is a rare true Science Hero, he definitely dabbles in the mad science spectrum as well, happily gloating about what a genius he is and occasionally wanting to test his new inventions on his allies. Of course, since it turns out that Sento was Takumi before he lost his memories, this is still a significant improvement in behavior.
Profesor Memelovsky in Odisea Burbujas, has a time machine, a size changing machine (that's how he managed to make a group of small animals human-size and become his assistants) and a machine to enter books.
Once Upon a Time had a Halloween Episode in which Princess Regina sought help in reanimating the (magically-preserved) body of her dead lover; that help came in the form of Dr. Frankenstein who conned her in order to steal a heart from her heart collection for his own creation. Frankenstein himself is a subversion. Everyone thinks he's this trope, and a few Storybrook residents react with suspicion once they figure out who he is. This gives him quite a bit of angst. He's understandably upset that his attempts at bringing his brother back to life are seen as evil. After Drowning His Sorrows and a heart-to-heart with the Big Bad Wolf ( Red Riding Hood), he decides to become an honest medical doc to disprove his reputation.
The Outer Limits (1995): In "Last Supper", Dr. Lawrence Sinclair is pursuing the immortal Laura/Jane (who he previously tortured as part of a secret military experiment) to obtain more blood from her, believing it can make him immortal too.
Sherlock Holmes from the BBC's Sherlock is constantly experimenting on something, including human body parts that he pilfered from the local morgue. Poor Watson even finds a human head in the refrigerator one day, and Detective Sally Donovan finds some human eyeballs in the microwave. And Mrs. Hudson finds a bag of thumbs in the fridge. That's scary and unsettling.
Samantha Carter is, occasionally, a benevolent variant on this, with McKay in one slightly forlorn moment noting that this is why she'll always be better than him — she's got an x-factor of pure inspiration that he doesn't.
O'Neill turns into this whenever an Ancient database is downloaded into his brain, cobbling together some exceedingly strange gadgets with junk lying around.
Linea, a woman known to many as the 'Destroyer of Worlds' for her twisted experiments with genetics and chemistry, and is arguably one of the smartest and most terrifying characters in the entire series - Doctor Frasier and Carter (the latter an example in her own right) both remark that she's so far ahead of them that it's terrifying. After being imprisoned for her crimes, and SG1 (who'd been locked up unjustly) broke out with her help on the assumption that she was as innocent as they were. She then more or less effortlessly crippled the SGC and left a creepy message behind, saying that it Makes Us Even.
Ke'ra is a benevolent variant on this, a brilliant chemist and geneticist. Unfortunately, she's the De Aged and amnesiac version of Linea, and is horrified by it. Eventually, after briefly getting her memories back, and being afraid of a Split-Personality Takeover, she intentionally loses her memories once more.
The Ancients were essentially a race of Mad Scientists. Exceptional mention goes to Janus and that guy who made the Ark of Truth.
Janus is benevolent, more so than most Ancients (he does everything he can to help an alternate Weir get to the present and save Atlantis from its fate in her timeline, against the will of his people, and is generally delighted that humans will eventually more or less catch up to the Ancients). However, he's mostly known for not one but two crazy inventions: a time travel device (two of them) and a device that destabilizes hyperspace in such a way as to destroy any Wraith ship that attempts to jump to FTL. The latter (called the Attero device) has a slight side effect. That being the destruction of any Pegasus stargate that is opened with a huge explosion. And what does he do once he realizes what the Attero device does? He shuts it down and leaves it intact in his lab. So, benevolent, brilliant, but not all that sensible.
Michael, in Stargate Atlantis, spends most of his time concocting various forms of monster through horrific human experimentation. He's also, arguably, the product of this himself, with the Atlantis Expedition having tried to 'cure' the Wraith with a retrovirus, and he ends up getting stuck halfway between the two.
A recurring theme in The Starlost. Scientists were rarely shown in a positive light, which is really weird for a science-fiction series. One scientist is conducting highly unethical social experiments on people, pitting them against each other. Another scientist, feeling nihilistic, hacks into the spaceship's computer system and activates the self-destruct system. An astronomer wants to study a comet up-close, so he steers the ship into the comet's debris field, not especially concerned that by doing so, the ship will probably be destroyed. Another scientist has been breeding giant mutant bees. None of them are interested in fixing the ship's engines to avoid their collision course with a star.
Degra, Dr. Crell Moset, Dr. Chaotica and numerous other specimens can be spotted on every incarnation of the franchise.
In Star Trek: Deep Space Nine, Dr. Elias Giger fits the profile of the more comic, probably harmless type. His theory is that death is caused by "cellular ennui," that cells can literally be bored to death, and so he creates his "cellular regeneration and entertainment chamber" to keep them stimulated. However, his work is supposedly hampered by non-believing "soulless minions of orthodoxy" and he seems badly paranoid that they are out to ruin him and his work.
On Star Trek: Picard, Altan Soong (son of cyberneticist Noonien Soong) introduces himself as a mad scientist when he meets Picard.
In the Supernatural episode "Time Is on My Side", the brothers encounter Doc Benton, a Mad Scientist who has used Mad Science to make himself immortal, but often needs to kidnap people and steal their organs when his old ones wear out.
Played with in the Dr. Death sketch on That Mitchell and Webb Look. Dr. Death is closely modeled on a German immigrant scientist (see Real Life) who has been working in secret on technology to help America win the war. Parodied in that his first invention is a laser, a.k.a. Death Ray, that's used to... scan the barcode on a can of beans, and he's disgusted when the president wants his creation used for destruction. Later played straight when Dr. Death unveils his Death Scorpion (with a gatling gun to dispense helpful bullets) and he also tries to destroy it when it's to be used for the war effort.
Dr. Death:NOOOOO!(seizes hammer) President: Professor! Dr: Death:(shouting over hammer blows) Forgive me, Mr. President, but I created the Laser-Fitted Armored Scorpion of Death to help mankind, not to destroy it!
White Rabbit Project: Tory claims that he's scared that Grant is a normal mad scientist in the Super Power Tech episode.