50nl - rivered 2 pair vs some random facing overbet

guy just sat down bought in for this amount.

I'm guessing this is just a standard muck until we get some sort of read right?

(sorry if this is a bad hand to post I've just been going through some weird variance where about 9/10 times on the river I get shipped on by these guys and always end up with a hand that I wanna showdown yet can't really stand an overbet...)

only a gutter or better 2 pair got there, but I would think he'd just keep betting an ace..which leads me to think this is a busted flush draw or worse 2 pair/chop pretty often. thoughts? this kinda makes me want to call..but the price is terrible

PokerStars No-Limit Hold'em, $0.50 BB (6 handed) - Poker-Stars Converter Tool from FlopTurnRiver.com

BB ($25)
UTG ($96)
MP ($147.65)
CO ($67)
Hero (Button) ($62.85)
SB ($24.55)

Preflop: Hero is Button with 8, 9
3 folds, Hero bets $1.50, 1 fold, BB calls $1

Flop: ($3.25) 5, A, 9 (2 players)
BB bets $2, Hero calls $2

Turn: ($7.25) 4 (2 players)
BB checks, Hero checks

River: ($7.25) 8 (2 players)
BB bets $21.50 (All-In)

dun think I can fold. Fishy buy in amount, fishy donk lead on A high flop and you have the second nuts. Looks too much like he is turning whatever one pair he has into a bluff.

Folding, this is such a mega value line. I see no reason for him to randomly turn one pair (especially top pair) into a bluff ever. It feels gross, but I feel this is very, very rarely a bluff nor a thin value shove. Yeah the more I think about this, the more it's definitely a fold.

i fold. Alot of the time i think he whiffed his turn c/r and wants to make up for missed value.

fold unless you've seen him make this type of bet with worse ever...

I'm also in the fold camp with no history.

Whats the best hand you guys would fold here?