Retreat to Coralhelm + Scaled Herbalist + Izzet Boilerworks

Retreat to Coralhelm

Scaled Herbalist

Izzet Boilerworks

How it works

1. Activate Scaled Herbalist by tapping it, putting Izzet Boilerworks from your hand onto the battlefield.
2. When Izzet Boilerworks enters the battlefield, it and Retreat to Coralhelm trigger.
3. Resolve the Izzet Boilerworks trigger, returning itself from the battlefield to your hand.
4. Resolve the Retreat to Coralhelm trigger, untapping Scaled Herbalist.
5. Repeat.