Requires

Dual Strike must be in hand, or in exile. Insidious Will must be in hand. You have a way to cast an additional instant or sorcery, or an opponent is casting one. Mana needed: , plus an additional if Dual Strike was not foretold, plus enough mana to cast the additional spell if needed

Steps

1. Cast any other instant and/or sorcery spell, or wait for an opponent to cast one.
2. Holding priority, cast Dual Strike by paying , copying the next instant or sorcery spell you cast with mana value four or less.
3. Cast Insidious Will by paying , targeting the instant or sorcery spell cast in step 1.
4. Dual Strike triggers, copying Insidious Will, with the copy targeting the original Insidious Will.
5. Resolve the copy of Insidious Will, copying Insidious Will, with the copy targeting the original Insidious Will.
6. Repeat step 5.

Results