Steven Universe's keystone: Ideas?
So I just found out that all story packs come with a unique keystone via the E3 presentation posted on the oficcial Facebook page. What do you think it should be? The 2016 ghostbusters has pocket universe travel, so something only vaugley related is acceptable. Although i'm already planning on giving the Homestuck story pack a time-travel keystone, so don't suggest that one, nor pocket universes, because as I already stated, The New Ghostbusters comes with that power.
I'm hoping for ideas soon, so don't be late!