Billy is wearing a necklace. I've never gotten a good look at it before.

I mean, its technically Dacre's actual necklace, but still. IT FITS SO FUCKING WELL

Its a Saint Christopher medallion.

Saint Christopher is the patron saint of protection. Its totally in my headcanon now. Billy's mother gave him that necklace...and it was the only thing that helped him fight the Mind Flayer when he did. That and El making him remember. Just...

dying