PokerStars No-Limit Hold'em, $0.50 BB (5 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Hero ($48.50)
SB ($49.55)
BB ($94.50)
UTG ($42.95)
MP ($60.45)

Preflop: Hero is Button with A, K.
UTG raises to $2.5, 1 fold, Hero raises to $7.5, 1 fold, BB calls $7, UTG folds.

Flop: ($17.75) 8, 6, T (2 players)
BB bets $33.5, Hero ???

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Villian is a complete unknown.

What does action like this usually mean, and do you make the call?