How common are these guys?

[modnareno]

I had a crazy african american guy raise to $20 in a 1-2 NL game - I called with AA and only another $20 hoping for overcalls, but everyone folded. Flop is 322 and he gives me the old "oh just you an me, I check." I stick my last $20 in there and he gets all pissed.

"Man I thought we was just gunna check it down!"

He calls and flips over 27o for trips. I turn an A and don't really know what to think.