Shadow Orb

Creatures you control with counters on them become Corruption in addition to their other types. When you put a counter on a permanent you control, put a Corruption counter on this card. {1}{U}{B}, {T}: Sacrifice this artifact. Search your library for a creature with converted mana cost less than or equal to the number of Corruption counters this card had when it was sacrificed, put it onto the battlefield tapped, then shuffle your library.