i think he hit trips, or has 2 pair, at those limits its impossible to get them off 2 pair
so the over betting here is to stop the flush, im pushing the turn....and they will probably call

had a str8 on the flop the other day at this .10nl .... on the river i bet 2$ and the guy called me with A8, no str8 draw no A no 8 on the board....called 2 dollars with A high

so they might just be trying to bluff....