Crackdown Construct + Frenetic Efreet

Crackdown Construct

Frenetic Efreet

How it works

1. Activate Frenetic Efreet's ability.
2. Hold priority and repeat this an arbitrarily large number of times.
3. Resolve the Crackdown Construct triggers, making Crackdown Construct arbitrarily large.

This loop relies on a brilliant interaction between Frenetic Efreet's zero-cost activation and Crackdown Construct's ability to capitalize on non-mana activated abilities. Because Frenetic Efreet's ability costs nothing to use and is not a mana ability, you can activate it repeatedly in response to itself without ever having to actually resolve the coin flips or risk losing the creature. Each of those activations safely stacks up on the stack, triggering Crackdown Construct over and over again to pump its power and toughness to astronomical heights.