1. A large wild bear who hath consumed ecstasy pills.
2. Someone who has consumed ecstasy pills and their effects are similar to that of a wild animal or beast.
1. I was walking through the forest with my homies and out of nowhere a giant thizzly bear popped out and tried to kill us.
2. "Did you see Nathan the other night?". "Yeah he was so twacked out he looked like a thizzly bear!"