Can you tell me anything about warp spasm?

Question

I'm writing a book and subject quite interests me.
If you don't have a clue, check out later, I'll put a "definition" up.

Answer 1

Sorta like a twisted seizure?

Answer 2

A mythological feat found in Celtic myths by which warriors enter a frenzied state of contortion in battle that makes them invincible. Those undergoing a warp spasm are said to grow so angered that their skeleton literally turns inside out in their bodies. The Irish mythological hero Cúchulainn is particularly associated with the warp spasm. In it, it was said that every hair on his body would stand out straight, with a bead of blood on the tip, and his skin would turn inside out and move about of its own accord.