Heidar, Rimewind Master + Intruder Alarm + Dual Nature + Ashnod's Altar + Ornithopter

Heidar, Rimewind Master

Intruder Alarm

Dual Nature

Ashnod's Altar

Ornithopter

How it works

1. Cast Ornithopter by paying 0.
2. When Ornithopter enters the battlefield, Intruder Alarm and Dual Nature's first ability triggers.
3. Resolve the Intruder Alarm trigger, untapping all creatures.
4. Resolve the Dual Nature trigger, creating a token copy of Ornithopter.
5. Activate Ashnod's Altar by sacrificing the Ornithopter token, adding CC.
6. Activate Heidar by paying 2 and tapping it, returning Ornithopter to your hand from the battlefield.
7. Dual Nature's second ability triggers, exiling nothing.
8. Repeat.

This intricate loop relies on Heidar, Rimewind Master acting as a persistent bounce engine, provided you control at least four snow permanents to fuel his ability. Every time you recast Ornithopter for free, Dual Nature steps in to generate an extra token copy, while Intruder Alarm catches the entry to untap your entire board—including Heidar. You then feed that token to Ashnod's Altar for mana, using those colorless funds to let Heidar return the original Ornithopter back to your hand so the whole cycle can begin anew.