I don't have the hand history but I'll try to make one up to roughly what it was.
SnG tourney $10+1. About 10th hand in. Blinds are 30/60, everyone started with 2000chips and not much has happend so far.
Hero is cut off with
couple of limpers, hero raises to 200. 1 Fold, BB Calls
Flop:
BB Checks, Hero raises to 400, BB raises to 1960 (all-in).
Now at this point i'm thinking WTF? I nearly put it down thinking he must have caught trips or 2 pair, then I thought it was a $10+1 SnG and he could have top pair ace kicker or something along those lines so I called
Villain Shows

(WTF????)
Luckily my Queens held up, he had a couple of extra chips to me so he stayed in for 1 or 2 more hands. In that time I asked him what he was playing at coming over the top of a 400 chip raise with Bottom pair. He said "I thought you were bluffing"
What a plank! I love $10+1 SnGs.
What could possibly make him think I was bluffing, and even if I was, surely he'll have a better chance to catch me at it than with bottom pair.
Would anyone have put this down (keeping in mind that it was a $10+1 SnG)?