The Demon Core

At the beginning of your upkeep, each player gets a rad counter.

{2},{t}: Put a charge counter on the Demon Core

Whenever one or more nontoken creatures you control die, put a charge counter on the Demon Core.

{6}, {t}, Sacrifice two creatures: Remove all charge counters from this artifact, then put twice that many rad counters on target player, then exile The Demon Core: