I like the reraise on the flop to $50. If he calls that imo he's on something big.
Well , he did one better than that. Youir $31 call to his raise gives you about 5:1 odds. You have 3 sevens (not the spade 7) and one 9, not the spade nine to make youir hand, and not fill in the flush when doing so. 4 outs in 48
=11:1 on turn and 11;1 on river = abut 5.5 to one. Your call is about even money.
Do i think he has a set. Absolutely no doubt in my mind; or he's a poker crazed maniac, lol