Morophon, the Boundless + Stonecloaker + Leyline of Mutation

Morophon, the Boundless

Stonecloaker

Leyline of Mutation

How it works

1. Cast Stonecloaker by paying 0.
2. When Stonecloaker enters, it triggers, returning itself from the battlefield to your hand.
3. Repeat.

This loop is a masterclass in bending alternative costs to our will, fueled by the clever rules interaction between Leyline of Mutation and Morophon, the Boundless. Since Leyline of Mutation lets us cast spells by paying {W}{U}{B}{R}{G} instead of their mana cost, Morophon, the Boundless steps in with its chosen creature type to make those exact colored mana symbols completely free. Because Stonecloaker is a Changeling, it counts as every creature type and benefits from this massive discount, reducing its cost to a neat {0}. When Stonecloaker enters the battlefield, its mandatory self-bounce trigger forces it right back to your hand, allowing you to recast it immediately for zero mana and generate infinite enters-the-battlefield triggers, leaves-the-battlefield triggers, and storm count.