Barely any hands on villain, 55/36 with 20% 3bet but probably too early to say he's a maniac, could be almost any player type I guess on a little heater over so few hands (13). I'm going to say he's an unknown for the purposes of discussion.

Anyone feel like he can do this often enough with 2 pair, sets or a busted flush even on this river to want to look him up?

Also, how many queens can he have? But even if he can't have many, does he do this with worse?

Poker Stars, $0.10/$0.25 No Limit Hold'em Cash, 6 Players
Poker Tools Powered By Holdem Manager - The Ultimate Poker Software Suite.

BTN: $14.55 (58.2 bb)
SB: $29.19 (116.8 bb)
BB: $43.89 (175.6 bb)
UTG: $37.99 (152 bb)
MP: $33.92 (135.7 bb)
Hero (CO): $25 (100 bb)

Preflop: Hero is CO with K K
UTG raises to $0.75, MP folds, Hero raises to $2.25, 3 folds, UTG calls $1.50

Flop: ($4.85) 4 J T (2 players)
UTG checks, Hero bets $3, UTG calls $3

Turn: ($10.85) 9 (2 players)
UTG checks, Hero bets $5.25, UTG calls $5.25

River: ($21.35) K (2 players)
UTG bets $27.49

(Hero has $14.50 behind, calling to win $35ish getting 2.5:1).