It's an amulet.

[He spreads his hands and leans forward a little, jostling a rusted-out pot with his foot as he does so.]

Against transformation work. I make them sometimes. It'll only work once, but if something goes wrong - if somebody, like, mind-controls me and sends me on a rampage, or if powers get switched around - that happened once--

If anything like that happens, you'll be protected.