Overmind

Defender, If you control three or more
non-Structure creatures, Overmind has Hexproof.
When Overmind enters the battlefield, copy all
non-structure Zerg creatures unter your control.
At the beginning of your upkeep, you may draw
a card.
At all times, there can only be one card named Overmind in the Game.
All non-structure Zerg units, have +2/+2.
When Overmind leaves the Battlefield, shuffle it
back into your library.