Errant, Street Artist + Reality Spasm + Doublecast

Errant, Street Artist

Reality Spasm

Doublecast

How it works

1. Cast Reality Spasm by paying at least 3, targeting at least three permanents and choosing the untap mode.
2. Holding priority, cast Doublecast by paying its mana cost, copying Reality Spasm, targeting at least three permanents.
3. Holding priority, activate at least two mana-producing permanents you control by tapping them, adding at least 1.
4. Activate Errant by paying 1 and tapping it, copying the Reality Spasm copy, targeting Errant and at least two mana-producing permanents you control.
5. Resolve the copy of Reality Spasm from step 3, untapping Errant and at least two mana-producing permanents you control.
6. Repeat from step 3.

This loop hinges on a clever manipulation of copied spells: because Doublecast copies your initial cast of Reality Spasm, that copy was *not* cast itself, making it a legal target for Errant, Street Artist. By sinking mana into a large value for $X$, Reality Spasm untaps both Errant, Street Artist and your mana-producing permanents, leaving you with enough fuel left over to activate Errant, Street Artist's copying ability again. This creates a self-sustaining engine that generates infinite magecraft triggers and infinite mana from your permanents.