Guess you're not the only one that something strange has happened with an arrow.

"I found an arrow in the skelleton of a dead animal with my warrior and wizard.
when i take it in my hand with my wizard, he starts jumping, my warrior gets invisible when he stands still


what does this do?"

This was a post titled Weird Arrow in the Helps/Tips/Tricks section. No one seemed to have an answer other than the arrow holding no importance.