NWI NL 1/2
Hero is at about $250. I'd been there for 3 hours and mostly treaded water. I bought it for $200.
Villain is in BB with $200. He's just rebought. He's been stacked twice already. He's the biggest maniac I know. A classic problem gambler. He's an ex-baller. I can only assume he saved something from the pros. Where does all that $ come from otherwise? Villain is a 35yo WG. I honestly think he likes to lose. He comes to the casino with 2 to 5 grand and loses it all. He likes slots too and is a "slots player." He's been kicked out of another Chicago area casino. I don't know why. He's not abusive and you'd think the casino would love him to death.

Hero wakes up UTG with KK I raise to $15 which is a big raise in the afternoon game (before villain came to the table). Once he got there everyone has been taking cover. It folds to villain who calls.
POT $31.
FLOP A82
BB donk bets for $20.
Hero--call? reraise?
I would have bet $25 on the flop had he checked it to me. What's best practice here? I'd say what's GTO but pikers like me shouldn't use that term.

I generally call because this could be anything and we are drawing to the nuts. If he has complete air he folds to a raise.

+1. If he has AJ or AQ with a spade he isn't folding, and if he has air with a big spade we want to keep him in the hand. He may stack off if a non-board pair spade comes.

Sound advice, I've seen the fellow spaz so often i feel like his bets are often completely disconnected from what he actually holds.

I am probably just calling his flop bet, I don't think a raise really ever accomplishes anything favourable here for you. Folding out his worse/air hands and probably (never) folds out any of his AX hands. And your hand is obviously drawing to the nuts.

I he will fold a draw, call. Raising just let's him fold. However, if this guy will call with a draw, I raise. I don't mind getting it in here for 100bb with my draw vs his worse draw, obviously.

If he's only donking with an A or flush, just call because I doubt he's ever folding. I just hope you get paid when you hit.

W/o knowing which, just call.

If he has a made hand that can stand a raise, he's winning. If he has a draw or nothing, you want him to keep betting. Hard to see what raising would accomplish. Against a non-maniac at least they might fold a bad ace, but not much chance of that here.

Easy call.

Call most of the time. Min raises also are great here. He is calling almost all hands he bets 20 with. Min raises are great when your in position vs a loose player. Builds a pot. Really confuses alot of players.