You Found Me
For pushkin666's prompt "red leaves in my hair" for April Fools' Fanwork challenge.
So the story is, Sam finds a spell or some black magic which transports him to purgatory, but he somehow can't maintain the form of his body and he transforms into some kind of an almost immobile purgatory creature. He can't speak or see, but he can carve words into the leaves that grow out of him. And that's how he finds his brother, or the other around.