Requires

Expansion // Explosion must be in hand. Fork must be in hand. Mana needed: , 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 Expansion by paying , copying the next instant or sorcery spell you cast with mana value four or less.
3. Cast Fork by paying , targeting the instant or sorcery spell cast in step 1.
4. The delayed trigger from Expansion triggers, copying Fork, with the copy targeting the original Fork.
5. Resolve the copy of Fork, copying Fork, with the copy targeting the original Fork.
6. Repeat step 5.

Results