Madman's Cauldron

{3}{p/b}, {t}, Sacrifice a creature: Search your library
for a creature card with converted mana cost X or
less, where X is the sacrificed creature's converted
mana cost plus one.
"Last time I used this thing, I stuck my friend Brian
into it. Now, the world has two Danny Devitos in it.
I'd say it works pretty well!"
-Elon Musk