Mortas, King of Slivers

+1: Put X loyalty counters on Mortas, King of Slivers, where X is the number of Sliver creatures you control.
-5: Search your library for a sliver permanent and put it onto the battlefield, then shuffle your library.
-20: You get an emblem with "Sliver creatures you control gain: Flying, Hexproof, Indestructible, Haste, First strike, and Deathtouch.