Requires

Sevinne, the Chronoclasm must be on the battlefield. Increasing Vengeance must be in the graveyard. Mana needed: plus enough mana to cast the instant or sorcery from your hand

Steps

1. Cast any instant or sorcery spell.
2. Holding priority, cast Increasing Vengeance for its flashback cost by paying .
3. Sevinne triggers, creating a copy of Increasing Vengeance, targeting Increasing Vengeance.
4. Resolve the copy of Increasing Vengeance, creating a copy of Increasing Vengeance, targeting Increasing Vengeance.
5. Repeat step 4.

Results