Azlask, the Swelling Scourge (Borderless)

Whenever Azlask, the Swelling Scourge or another colorless creature you control dies, you get an experience counter. WUBRG: 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.