Too Dumb to Live/Web Comics

"Muffin: You stupided yourselves into extinction."
 * Fighter from Eight Bit Theater. In fact, he's so dumb he can't even BE killed.
 * Fighter isn't the only one. Black Mage also qualifies, most famously for his fondness of solving every problem with nuclear blasts, having apparently once used it on a bee. It gets worse when it turns out that he can only use his nuke spell once per day, and favors using his knife over other spells (he repeatedly tries to kill Fighter with it, with no success), and when once suggested that he use a lower-than-level-9 spell, he said they weren't his idiom. Aside from this, there's also his attempts at hitting on White Mage, which usually result in her beating him to a pulp. Red Mage also falls under this, once being too dumb to use white magic on himself after getting his ass kicked by werewolves, and once not noticing a bridge across lava that Fighter and Black Mage notice. Even Thief gets this as this strip shows. In spite of this, all four of them have some moments of intelligence.
 * The entire order of the Red Mages, there's a reason Red Mage is The Last of His Kind. You see, they held their elaborate, secret meetings, while other people were busy finding mates and reproducing. This, combined with their trying to find the underlaying rules of how the universe worked by hitting each other with random weapons and spells to see how much damage they did, sort of resulted in, well... as Muffin so aptly put it:

"Schlock: They committed suicide when they saw me coming."
 * you can't forget Black Belt, who once got so lost travelling down a straight hallway that he ended up tearing a hole in space/time, resulting in him being followed around by a time duplicate of himself from one second in the past.
 * Sapphire Gem from Monsterful, all her "special" moments could have their own page.
 * Since she's a zombie she's already dead anyways.
 * Gordon Frohman from the Half-Life-based comic Concerned is quite possibly the definition of Too Dumb to Live
 * With full knowledge that the device before him is a bomb (as it gets hinted that he himself planted it there) and with apparent full knowledge of how to disarm said bomb, Captain Broadband still comes to the conclusion that the best way to resolve the situation is to treat the bomb like a PSP and punch it out of anger for the square button not working correctly. He survives, though the next issue reminds us that he had died in the previous issue.
 * Girl Genius: "I will shoot any man who tries to move this ship". Not only is this guy as good as dead, he just doomed the whole crew with him (well, assuming they could have made it out in time).
 * Background character mentioned only in passing, but: X The Destroyer is definitely an example.
 * Also, Snapper, who once he learned "Wilhelm" was actually immediately tried to take her hostage. She then kills him with a single kick and even the other inmates start claiming how stupid this was, earning him a place on this list.
 * Torg (and sometimes Riff) take this role occasionally in Sluggy Freelance. Probably the most extreme example was when they summoned a demon with the power to destroy the world just so it would give them a case of beer and $20 in cash. If the demon hadn't been a few cents shy of the full twenty, the series would have been a lot shorter.
 * Casey and Andy may be brilliant inventors, but they're literally Too Dumb to Live, since they get killed constantly. Trick juggling near unprotected anti-matter, skydiving but forgetting to pack the chutes, the wood-powered submarine with the chimney... The list is WAY too long.
 * Bob and George parodies this by noting that one of the main characters has the "extraordinary ability to not recognize life-threatening injuries." In other words - he's too stupid to die.
 * In Book 10 of Schlock Mercenary, the inhabitants of the Credomar Habitat use fuel-air explosives inside their space station as part of a protest march.
 * And then there's the ones who kept enough anti-matter around to create an eighty-megaton explosion and didn't even bother to fire-proof the containers. As it turns out, fuel-air explosives and fullerened anti-matter don't mix...
 * You have to see it to believe it... but Schlock's description is accurate:

"Dweebley: What the? Oh, for - BWAHAHAHAHAH!! [...] I'll admit Federation design philosophy is backward in a lot of ways... But we're not suicidally insane... Wait... are these shuttles real??"
 * Leo from VG Cats. The examples are too numerous to list them all, but one includes him going back in time and cutting off his younger self's arms, just to see if his own would turn into stumps. And they did.
 * Given that Aeris had given his mother an abortion two strips previously and Leo got better, and that young Leo seems just as enthused about his future self's arms being cut off, Leo's a textbook case of Too Dumb to Die.
 * Joey from A Game of Fools.
 * Kaalinor of Anti-Heroes. Fortunately, he's already dead, so his stupidity can't cause him further harm.
 * Quentyn Quinn, Space Ranger. Thus far, the title character has had to deal with nothing BUT this sort of alien... first with a crew of "space pirates" who manage to get eaten by their third would-be hijacking victim; then the blue-skinned Federation aliens who run their ship with an exposed antimatter reactor, have crackerbox computer security, fly shuttlecraft with the aerodynamics of a cement block, and use matter-transporter technology despite having at least one crewmember who has been grotesquely mutated and deformed by its chronic use....
 * It only gets better later, when it's turn of The Cold Equations to be mocked. Especially as they invited along the Only Sane Man from Federation ship and had his comment on the ideas of reliability involved in this setup:

"Roy: I tend to see Elan more as an obstacle that this team overcomes on a regular basis."
 * Elan, early on in Order of the Stick. "Bluff, Bluff, Bluff, Bluff the stupid ogre!" Summed up by the team leader:


 * Also from that same quote...

"Roy: Traveling with Elan is kind of like, say, adventuring with syphilis. It can be done, for a while, but it's not easy and it's not pretty."

"Haley: How can you be so smart sometimes and still be such... an airhead!?"
 * Some fans also think that Celia the Sylph is this by way of Stupid Good, due to her pacifism and her willingness to do things like ignore the obviously evil surroundings of Greysky City, and Haley's explicit warnings, and wander off on her own with Roy's body. Haley certainly thinks so:

"This entire episode would never have happened if Starfleet had any sort of workplace health and safety policies whatsoever."
 * Crystal of the Thieves' Guild is described by Rich in the commentaries as being too dumb to live, and really only survives because she's got Bozzak thinking for her. The comics repeatedly demonstrate this fact.
 * Tsukiko, necromancer (and -phile) and one of Xykon's lieutenants, thought that because Redcloak tolerated her constant taunts and attempts to undermine his authority he was a submissive coward. So when she found out that he was betraying their master, she told him that she knew and was going to alert Xykon, expecting him to stand meekly aside and allow it. What really makes this Too Dumb to Live is that even if Redcloak was submissive, telling him that you're going to get him killed would certainly provoke a response--even a docile animal can be dangerous when cornered.
 * Many prey animals in Kevin and Kell display this behavior, such as walking into obvious predator traps, attracting attention to themselves while out in the open. Ray (a firefly) in particular isn't at all bothered by Lindesfarne being an insectivore.
 * On the other hand, Ray is a bit on the dim side. His moth wife Tammy is theoretically smarter, and she has a close friendship with said insectivore.
 * One of Larvova's Scourges in Drowtales makes the mistake of threatening Kiel'ndia in the presence of Kharla'ggen. His boss certainly seems to consider him this and walks away without another look at him.
 * The time-traveling paleontologist in this Dawn of Time strip. He fails to consider that he might be wrong about the T-Rex being a so-called "pure scavenger"... or that even if it were, there hasn't ever been a scavenger on Earth "pure" enough to avoid eating a small, easy-to-kill creature that's not even trying to get away... or that a running critter the size of a small truck won't need to do anything to kill him...
 * Freddy in Horndog.
 * Apparently, the two kids in this Xkcd comic are just bright enough to recognize Indian bones but not bright enough to recognize an Indian Burial Ground until after they've desecrated it (and no doubt invited all sorts of well-deserved supernatural horrors onto themselves - check out the Alt Text for more fun).
 * Happens sometimes in Cyanide & Happiness. Others began to count on it. Hey, if people can fall for the "iloveyou" virus...
 * Minmax of Goblins verges on this at times. It is played especially straight in this strip.
 * Tempts Fate managed to drown a score of hostile World of Warcraft PCs (It Makes Sense in Context) by telling them that if they submerge into water and wait until they run out of breath, they'll be teleported to a secret place full of loot and XP. And why did they listen to him when only moments before they were after his blood? Because he had an exclamation mark over his head that marked him as a quest-giver, which he stole from an actual quest-giver right before the eyes of said PCs.
 * Zeromus in Captain SNES falls for every stupid trick in the book, mostly because he's a personification of protagonist Alex's hatred. It just so happens that that the thing Alex hates most is stupid people.
 * A fan comic of Narbonic showed what happens when you create a lethal soda and advertise that it's deadly to drink.
 * Sinfest had a character dumber than this. Briefly. "I made fun of the Devil ]".
 * And character argue on the brink of Hell, with a sign up to warn them.
 * Looking for Group has a gnome guard on page 275 who makes a snide remark about Richard. While standing in arm's reach. Next to a pit of magma.
 * The Elves in Errant Story, with exactly two exceptions (Sarine and Misa [literally the youngest elf in the world]). The aftermath of the final battle brings this trope into full focus, when one of the surviving Elves  Not a single Elf on the scene so much as protests his words (Save, who's too exhausted and disgusted to muster the energy).
 * Ethan of Ctrl+Alt+Del. According to Zeke, if you run the data from Ethan's various misadventures, his life expectancy comes out negative. Negative forty.
 * Many of the characters of Girls with Slingshots have had their moments of overwhelming stupidity, of course Your Mileage May Vary.
 * This blogger makes a series of quick comics of Skyrim. About half of those are this trope.
 * Planet of Hats presents: The Naked Time. Not that they act more sane in the rest of recap, but here they repeatedly go out of their way to ensure their own demise.