Patchwork Crawler + Trench Behemoth + Llanowar Scout

Patchwork Crawler

Trench Behemoth

Llanowar Scout

How it works

1. Activate Patchwork Crawler using Llanowar Scout's ability by tapping it, putting a land from your hand onto the battlefield.
2. If the land is mana-producing and enters the battlefield untapped, you may activate it by tapping it, adding at least 1.
3. Activate Patchwork Crawler using Trench Behemoth's ability by returning the land from the battlefield to your hand, untapping Patchwork Crawler.
4. Repeat.

This clever loop begins by feeding Trench Behemoth into Patchwork Crawler's exile ability, granting the Crawler the Behemoth's skill of bouncing a land to untap itself. Once equipped with that engine, Patchwork Crawler can also adopt Llanowar Scout's activated ability to continuously drop that very same land right back onto the battlefield. This creates a perpetual cycle of bouncing and replaying your lands to endlessly untap Patchwork Crawler, which in turn generates infinite landfall triggers and infinite mana from any land that enters untapped.