PokerStars No-Limit Hold'em, $1.00 BB (8 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

MP2 ($93.50)
CO ($101.05)
Button ($41.45)
Hero ($108.05)
BB ($87.30)
UTG ($78.55)
UTG+1 ($102.25)
MP1 ($99)

Preflop: Hero is SB with Q, A.
3 folds, MP2 raises to $3, 2 folds, Hero raises to $12, 1 fold, MP2 calls $9.

Flop: ($25) J, 8, 4 (2 players)
Hero bets $18, MP2 calls $18.

Turn: ($61) Q (2 players)
Hero ???

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Villian here is a complete unknown.

What's your move here?