This clever loop relies on Pestilence as a repeatable engine, paying black mana to deal damage to everything on the board while carefully keeping itself alive by not wiping out all creatures at once. Each time the damage spreads, Sonic the Hedgehog's second ability turns that punishment into a massive influx of tapped Treasure tokens, as Sonic's haste ensures it qualifies for the trigger. That is where Amulet of Vigor does its crucial work behind the scenes, instantly untapping each Treasure the moment it enters the battlefield so it can be sacrificed right back into the pool. By feeding the generated mana back into Pestilence, you loop the entire sequence to flood the board with riches and burn out your opponents.