Shai-Hulud

Backup 3 (When this creature enters, put three +1/+1 counters on target creature. If that's another creature, it gains the following ability until end of turn.)

Whenever this creature attacks, look at the top X
cards of your library, where X is its power. You
may put a permanent card with mana value X or
less from among them onto the battlefield. Put the
rest on the bottom of your library in a random order.