Heart of Bogardan

Oracle text

Cumulative upkeep {2} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) When a player doesn't pay this enchantment's cumulative upkeep, this enchantment deals X damage to target player or planeswalker and each creature that player or that planeswalker's controller controls, where X is twice the number of age counters on this enchantment minus 2.