Tourach's Chant + Dryad Arbor + Mikaeus, the Unhallowed + Aether Flash

Tourach's Chant

Dryad Arbor

Mikaeus, the Unhallowed

Aether Flash

How it works

1. Play Dryad Arbor.
2. When Dryad Arbor enters, Tourach's Chant and Aether Flash trigger.
3. Resolve the Tourach's Chant trigger, putting a -1/-1 counter on Dryad Arbor.
4. Dryad Arbor dies as a state-based action due to having 0 toughness, triggering its undying ability, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
5. When Dryad Arbor enters, Tourach's Chant and Aether Flash trigger.
6. Resolve the Tourach's Chant trigger, putting a -1/-1 counter on Dryad Arbor.
7. Resolve the Aether Flash trigger, dealing damage to Dryad Arbor.
8. Repeat from step 4.

This ingenious loop turns the humble land-creature Dryad Arbor into an infinite engine for triggers by weaponizing its own fragility. As Dryad Arbor enters the battlefield, Aether Flash and Tourach's Chant both trigger, allowing you to alternate between dealing damage and placing a -1/-1 counter that shrinks the Arbor's toughness to zero. The magic that keeps this cycle spinning is Mikaeus, the Unhallowed, whose static ability grants undying to your non-Human creatures—canceling out the -1/-1 counter each time Dryad Arbor dies and resurrecting it right back onto the battlefield to start all over again.