Do you give an unknown credit for a monster here?

Party Poker No-Limit Hold'em, $ BB (10 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

UTG+1 ($62.43)
UTG+2 ($51.65)
MP1 ($61.38)
Hero ($67.25)
MP3 ($59.05)
CO ($63.20)
Button ($57.35)
SB ($48)
BB ($38.90)
UTG ($41)

Preflop: Hero is MP2 with Q, Q. SB posts a blind of $0.25.
1 fold, UTG+1 calls $0.50, 1 fold, MP1 calls $0.50, Hero raises to $3, 5 folds, UTG+1 calls $2.50, MP1 calls $2.50.

Flop: ($9.75) 2, 8, 4 (3 players)
UTG+1 checks, MP1 checks, Hero bets $7, UTG+1 calls $7, MP1 folds.

Turn: ($23.75) 4 (2 players)
UTG+1 bets $52.43 (All-In), Hero ???