Thoqqua's are extremely silly monsters. They deserve all the ridicule and scorn you would expect for having the shape they have. I will not describe their shape here beyond the poster for I feel that would violate decency laws. They are not the most insane monster in the Monster Manuals, nor the most insane monster to ever be created. That is a poster for another time. Early in my current dungeon crawl I threw several thoqquas at my players. The innuendo flew fast and furious. The players were not amused. They didn't like the flaming part either. In any event I found it an enlightening experience in using crazy monsters against my players.
Let's hear about the memorable fights that you've had that were memorable simply because the monster was that messed up.