When I was a kid, we would buy these cheap "best friends" necklaces. They were usually a heart that was cut into two pieces. One would say "Friends" and the other would say "Forever" or something like that, so that you always knew who your BFF was (I don't know, I was like six).

This skull and brains version could beat the hell out of those old heart-shaped necklaces. Nothing cheesy about it: one of you gets the skull, the other gets the brains. Or be selfish and keep the whole set for yourself. I won't tell.