ohh...Tswv Xyas is the legend. Tswv Xyas has the power to turn himself into a tiger and back to human form...its a some what scary story. his story is one of the many stories i heard. tswv xyas is a very common one, if you ask your parent or any elder, they are able to tell you.
Well, i can't really learn much from my mother. Even though she really liked Hmong folktales as a child (and memorized them too, she also know some Laotian folktales as well),but she always covered her ears when my grandma told ghost storys or scary stories so she never learned any of the scary ones. I'll try asking my grandma from my dad's side, maybe she might know something about it.