Quads he'd slow play which I agree, but I also think if they had 8x they would be slow playing as well, given you can't really call a raise with anything other than Kx/AA which is a super thin range to target.

Whether I call or fold the river depends on how I view villain. If he is a standard ABC reg who no tricks, I give him credit for a hand and fold, if he's got moves, then his line to make makes no sense and I call.

I kind of think your flop check gave them the idea to fold you off Ax or a PP lower than Kings.

This is really tough at 50NL where villains will be often be capable of trying to move you off a weak Kx.

It looks strange that he would expect you to call a raise with much that checks the flop, or at least the follow through on the river as well. One of those spots where we don't beat anything he plays this way for value, but it looks a bit ham fisted to me so I would call as played.

Did you consider checking the turn as there's not a lot which will call two streets that we beat?

Interesting hand - I like the flop check, once villain checks back I'm checking that turn too with BD fl draw - inducing bluffs or allowing myself to get 1 street of value on the river vs villains under pairs/A high type hands. We're going to want to check flop with all of our 99-QQ and likely the turn too so having some Kx makes a lot of sense.

As played he definitely plays all his 8x like this, but I wouldn't be folding he can show up with enough busted fl draw combos to make this fine. Sigh call and give myself a slap for betting turn.