Gurglag, the Mass Eater

Gurglag cannot be blocked by creatures 3 or greater.
When you cast Gurglag, it enters with X +1/+1 counters on it. If it enters with five or more counters on it, put a bubble counter on each creature you control. They become green oozes in addition to their types and colors. They cannot be blocked as long as Gurglag is on the battlefield. If Gurglag leaves the battlefield, remove all