There was some confusion as to how many "bad ends" there are, or how exactly to get some of them, so I found out. There are in fact 17 unique bad ends listed below, with the correct name used in the game code (and savefile!) in quotes.

Some have more than one cause and will be written cause1, cause2, ...

"Mangled" - Biter.
"Melted" - Touch Meltie acid.
"Impaled" - Sharp.
"Squashed" - Grinder.
"Chowed" - Fuzzle.
"Speared" - Impaled by Gray lance.
"Burned" - Fire.
"Shattered" - Bumped while frozen.
"Absorbed" - Touch Oozle, Touch Amalgam, Touch Gray(When not hard or using lance).
"Disintigrated" - Void eater beam.
"Gibbed" - Touch Razor Queen tail, Inside Instant wall, any explosion (void eater wave, grenade, torchie, ...).
"Hooked" - Horror hooks, Razor Larvae spikes (The one that explodes when you get close).
"Stapled" - Razor Quill (The spike projectiles that carry you off screen).
"Split" - Razor Mite (The one that digs).
"Splattered" - Touch horror (While complete).
"Piked" - Razor Hedgehog (Thrown spike ball, even if it lands on top of you).
"Sliced" - Any queen or razor queen claw, Horror discs, Saw Drone (50% chance of decapitation/bisection animation).