Guy with quads raises hell about my play...wtf??

[PAUL-IN]

so i'm playing the borgata $250+30 last week. 400 players.
about 70 left and i'm in big blind with 8 [img]/images/graemlins/heart.gif[/img]5 [img]/images/graemlins/heart.gif[/img]. blinds about 800-1600, not sure. i had about 40K, button was big stack at 60K.

only limper is on button, SB folds.

flop is 8 7 7. i check, button checks.

turn is 8. i bet min, 1600. he flat calls.

River is 8. I check, he bets 8000, i raise him to 21,000. he goes instantly all in. I of course call.

he slams down 77 and starts yelling at me about the hand. if anyone played that deep at that tourney, you probably heard him screaming. Everyone got a good chuckle out of that one.

WTF did i do wrong?? LOL.