Errant, Street Artist + Reality Spasm + Twincast

Errant, Street Artist

Reality Spasm

Twincast

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 Twincast 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 uses Twincast to kick off a chain reaction with Reality Spasm, letting you untap your lands and permanents over and over again. The secret sauce is Errant, Street Artist, whose active ability lets you repeatedly copy the copied spell without ever casting it from your hand. By channeling your mana back into the engine with each iteration, you generate infinite untaps and infinite mana of any color your permanents can produce.