Bottom set........but smell an overpair

[anti_unreal]

Party Poker, $1/$2 NL Hold'em Cash Game, 6 Players
LegoPoker Hand History Converter

UTG: $183.27
MP: $137.05
CO: $109.66
BTN: $180.10
SB: $238.70
Hero (BB): $198

Pre-Flop: 2[img]/images/graemlins/heart.gif[/img] 2[img]/images/graemlins/spade.gif[/img] dealt to Hero (BB)
UTG calls $2, MP folds, CO calls $2, 2 folds, Hero checks

Flop: ($7) 9[img]/images/graemlins/heart.gif[/img] 5[img]/images/graemlins/diamond.gif[/img] 2[img]/images/graemlins/club.gif[/img] (3 Players)
Hero checks, <font color="red">UTG bets $10</font>, CO folds, <font color="red">Hero raises to $20</font>, <font color="red">UTG raises to $181.27 and is All-In</font>, Hero???????


Bad play by calling the crai on the flop? The huge reraise immediately makes me think im against an overpair......thoughts?????