Azlask, the Swelling Scourge

Whenever Azlask or another colorless creature you control dies, you get an experience counter.

{W}{U}{B}{R}: Creatures you control get +X/+X until end of turn, where X is the number of experience counters you have. Scions and Spawns you control gain indestructible and annihilator 1 until end of turn.