"The ultimate villain of the story, who's causing the problem the heroes must solve."
Note that Big Bad is not a catch-all trope for the biggest and ugliest villain of any given story. The BigBad is the one who turns out to be behind several other seemingly independent threats.
* The Big Bad of ''BrokenSaints'' fits this to a T, down to his identity being unknown until the brilliantly timed closing epigraph of the penultimate chapter: [[spoiler: "'Tis the time's plague when madmen lead the blind." -- King ''[[MeaningfulName LEAR]]'']]
* ''SuperMarioBrosZ'''s primary Big Bad is Mecha Sonic, though Bowser and [[spoiler:Dr. Eggman]] are a close second.
* In ''BananaNanaNinja'': Banana Shop of Horrors, the Big Bad is I.R. Kostlowski, the manager of the [=PriceCo=] Supermart who refuses to stop selling bananas for food after hearing the banana ninja's [[SamuraiJack pleas to free them]]. He engages Baninja in a [[SwordFight pencil-to-tiny sword]] BossBattle to defend his "best wholesale contract."
* In [=KlayWorld=]: Off The Table, King Womp is this. [[spoiler:When he and his fellow "aliens" (that is, peach-colored clay people instead of blue ones) come upon the Table's Klaymen, his reaction seems neutral... at first.]]
-->[[spoiler:'''Womp:''' ''(makes his appearance, looks at the Klaymen)'' Wow. We've got a lot of stuff to improve here. ''(approaches Klaymen, folds hands behind back)'']]
-->[[spoiler:He proceeds to explain that his people journey all around the world, finding other clay civilizations and accepting them into their own... and says that the blue Klaymen are the worst.]]
-->[[spoiler: '''Womp:'''... I'm gonna be honest. You guys are probably one of the worst clay men we've ever run into. You're just blobs; there's nothing special about you. But I'm gonna do you a favor. I'm gonna cut you all apart, and we're gonna build you into something better.]]
-->The whole time, he has a scarily calm, reasonable, deadpan delivery (courtesy of Jason Steele) that sprinkles Nightmare Fuel through the Uncanny Valley.
* The "Shadowy Figure" to Stinkoman from the 20X6 universe from ''WebAnimation/HomestarRunner''. Too bad we never see him...
* SonicForHire has had a few of these per season.
** Eggman: Season 1, although turned into a Joke Villain and eventually [[HeelFaceTurn an ally for Sonic]].
** [[TheMafia Mario]]: Seasons 2 and 6.
** [[spoiler:Tails]]: Had a FaceHeelTurn for the last two episodes of Season 3 and entirety Season 4. [[HeelFaceTurn He turned back to normal in Season 5]] and got turned into a ButtMonkey.
** [[StarFox Fox McCloud and Falco Lombardi]]: The only real major villains Sonic deals with in Season 5. [[spoiler:Falco]] dies and [[spoiler:Fox]] gets his crew back.