As in instigator. Instigating posts made intentionally to piss you off. Not to be confused with trolls and their damn trolling, gator posts are done by someone PRETENDING to be against something. A gator touches a keyboard to push buttons for control of your mind or a thread.
Something or someone of exceptionally high quality, most commonly spoken from the mouth of a gator. (See definition for gator- i.e. "best pimp in the game")