He never plays around with something that 'would never happen.' That's how people die, Istredd. But Lucifer has enough of an idea about what to look for if they get into that level of Bad Day. It's all he needs, because while yes he does want to feel and see and experience Istredd really opening up his magic, he needs to know where the line is.

Well, good. What would I even do if you became an eel in the middle of some woods? I don't know, maybe magic eels can survive out of water. There's an odd, thoughtful pause from him. Not you, obviously, but if you eat a magic eel battery, do you gain their power? I mean, we can consume another angel's grace, so it's really much the same concept, I'd think.