Expansion // Explosion + Fork

Expansion // Explosion

Fork

How it works

1. Cast any other instant and/or sorcery spell, or wait for an opponent to cast one.
2. Holding priority, cast Expansion by paying U/RU/R, 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.

This loop turns a modest beginning into an endless recursion of copying by exploiting the delayed trigger on Expansion // Explosion. Once you have a valid spell on the stack, you cast Expansion to set up its copy effect, and then follow it up with Fork targeting your original setup spell. Because Fork is an instant with a mana value of 2, Expansion's delayed trigger sees it and immediately copies it, allowing you to point the new Fork right back at the original Fork. This creates a self-sustaining loop where every resolution of the copied Fork generates yet another copy of Fork, letting you repeat the process indefinitely to trigger any magecraft abilities you might have in play.