Castiel gave Bruce an amused look. Did he think that Castiel was bitten by a werewolf? Maybe he saw Castiel running with the wolves outside, rather than killing them in impressive numbers.

He tilted his head to the side. "You're more than welcome to experiment on me." Obviously, he had no idea what he was offering, but he saw no harm in it. Mina was his friend, right? She wouldn't hurt him and he wasn't even sure how much she could.