Another cracked Aces story, but WTF?

[Penguinfan]

$2/$4 limit holdem I get AA under the gun and raise (the correct thing to do here) get called by the guy to my immediate left and one other player plus the BB, flop is A-4-5, BB checks I bet, guy to my left calls, other 2 players fold, 8 on the turn, I bet and get called, river 9, bet and get raised, WTF could he have, WHAT COULD HE HAVE, did he chase a pair of 9' and catch a set, HOPE SO cause I got my own set and they trump his for sure, the betting gets capped and sure enough he turn over 2-3 for a wheel?!?!?!?!?!?!? I know it's low limit, I know people suck, I know he'll pay me off later, but 2-3 in early position against an UTG raise?????

I'm still steaming about this one.......