a fold unlike any other i've ever made

[Matt R.]

This bet was very likely an attempt to "freeze" you with his overpair, as he didn't want to be put to a tough decision by someone who is overplaying top pair. Looks like it pulled double duty by getting you to fold a monster as well. I think this is more likely than a bigger set given the board on the flop and his flop action. Folding is pretty bad, IMO, without some stellar reads.