Doppelgang + Echo Mage + Dominating Vampire

Doppelgang

Echo Mage

Dominating Vampire

How it works

1. Cast Doppelgang by paying 6, targeting Dominating Vampire and a mana-producing permanent.
2. Holding priority, activate Echo Mage by paying and tapping it, copying Doppelgang, targeting Dominating Vampire and a mana-producing permanent.
3. Resolve the copy of Doppelgang, creating two copies of Dominating Vampire and the mana-producing permanent.
4. When the Dominating Vampire tokens enter, they trigger, untapping Echo Mage and any other applicable permanent.
5. Holding priority, activate the two mana-producing permanent tokens by tapping them, adding at least .
6. Repeat from step 2.

This magnificent loop begins by casting Doppelgang with a massive investment of mana, targeting a mana-producing permanent and a Dominating Vampire to set the stage for an overwhelming cascade. By utilizing Echo Mage's activated ability at Level 4+, you copy that initial Doppelgang on the stack, allowing you to multiply your permanents exponentially as the copies resolve. Every iteration brings forth fresh token copies of Dominating Vampire whose enter-the-battlefield abilities trigger to untap your Echo Mage and other key permanents, while the newly spawned mana-producing permanent tokens are tapped right back for the blue mana required to keep the engine roaring.