Erakir, Angelic Anger

This spell costs {1} less to cast for each commander
you control.
When Erakir, Angelic Anger enters the battlefield, tap each creature with converted mana
cost less than the amount of mana you spent to
cast this spell.
{t}{w}: Tap target creature until Erakir leaves the battlefield. Activate this ability only if you have
cast Erakir twice this game.