Thing_Destroy
From ZDoom Wiki
133:Thing_Destroy (tid, extreme)
tid: Thing ID of the thing to destroy
Kills the specified thing. If you have a TID of '0' then it will kill all the monsters on the map, similar to the 'kill monsters' cheat. If extreme is 1 the thing enters its extreme (gib) death sequence if it exists.
Note that this function does not properly handle killing players with armor or more than 100% health if extreme is 0.

