Requires

Rootha, Mercurial Artist must be on the battlefield. Increasing Vengeance must be in hand. Mana needed: , plus enough mana to cast the additional instant or sorcery

Steps

1. Cast an instant or sorcery spell, or wait for an opponent to cast one.
2. Holding priority, cast Increasing Vengeance by paying , targeting the spell.
3. Activate Rootha by paying and returning it to your hand, copying Increasing Vengeance, with the copy targeting the original Increasing Vengeance.
4. Resolve the copy of Increasing Vengeance, copying Increasing Vengeance, targeting the original Increasing Vengeance.
5. Repeat step 4.

Results