My thoughts: Could the 'seeming angry' be a fake tell. ie, wants you to think he has a made hand when he is actually drawing.
I would expect him to be 3 betting pre with jj or kk and probably AQs+ too.
To me, the only hand that makes any sense for villian, which actually beats you, is
or the nut flush.
I would struggle to fold here, but i do think that a FOLD is the correct choice.
I think the nut flush certainly can't be ruled out. I guess a lot depends on your reads of villian. Although he seems weird, would he really be jamming into a flushing board with a not top set, against a player who's hand seems to be unde-repped (ie could have a flush draw).
As villian has position here, surely here would just check behind with most of his range of decent, but not nut, made hands?
If he was so eager to 5-bet the flop, could he really show up with a bluff on the river? I personally dont think so.