This man encountered the Trickster in his own domain. In the woods this spirit isn't acting out of simple mischievousness. In the woods he has something to protect and any human that gets too close won't be allowed to leave. At least not as a human.

The former man fell to the ground. He felt more comfortable with all four paws on the earth. The underwear dissolved into the air like the rest of his clothes. But he didn't need it anymore. bears don't wear underwear.