OK, I brought the bike over to my cousin's and he put the crank arm in a vice, put a pipe on the wrench, and slowly got the pedal off. Not surprisingly, the threads were stripped. Who knows how it happened, but a young person riding aggressively is the probable cause.

The bike isn't worth much of anything. Any kludgey fixes? The crank is one of those weird biospace kind of oval cranks. I wouldn't want to spend much to replace it.