The Ditz/Playing With

Basic Trope: A character who is so stupid it's unclear how they've managed to survive until now.
 * Straight: Bob's stupidity is of such baffling magnitude that it's unclear how he even functions.
 * Exaggerated: Too Dumb to Live
 * Justified: Bob suffers from a brain disorder that severely restricts his mental development.
 * Inverted: Bob is a TV Genius who is more competent than the rest of the cast put together.
 * Averted: Bob's stupid, but still vaguely capable of carrying out normal human activities.
 * Parodied: Bob's brain can be completely removed without any noticeable effect.
 * An intelligence-eating Puppeteer Parasite locks onto his head, and goes gray over the course of the episode. it finally falls off, and the COD is "Malnutrition. Poor thing starved to death."
 * Bob tries to think. His head explodes.
 * Subverted: Bob's revealed to have been the Big Bad pulling strings from behind the scenes the whole time while putting up an idiotic facade to avoid suspicion.
 * Double Subverted: Even after being revealed as the Big Bad, Bob doesn't display any signs of anything beyond the most basic cognitive functions.
 * Zig-Zagged: Sometimes Bob is presented as stupid, sometimes of average intelligence, and sometimes a genius.
 * Deconstructed: Seeing that Bob has absolutely no concept of morality or consequences and that nobody would ever suspect him of anything, Manipulative Bitch Alice convinces Bob to play a "game" with his friends involving a shotgun. Bob then spends the rest of his life in a mental hospital, with no idea why his friends won't ever come back.
 * This actually happened to Hod in Norse Mythology, only with mistletoe.
 * Reconstructed: To prevent him from being manipulated into harming anyone (including himself), Bob is always accompanied by his guardian/attendant Carol. Carol lampshades all the bizarre stuff Bob does and says, and - due to being constantly by his side - probably has a minor Butt Monkey status.
 * Lampshaded: "Bob isn't the brightest crayon in the box."
 * Enforced: "We need a character who makes even the stupidest characters look smart by comparison."
 * Invoked: Bob stands under a coconut tree and a very large coconut lands on his head.
 * Defied: Bob keeps his smarts up any way he can
 * Discussed: ???
 * Conversed: ???