Earthcraft + Fertile Ground + Horseshoe Crab

Earthcraft

Fertile Ground

Horseshoe Crab

How it works

1. Activate the basic land with Fertile Ground attached by tapping it, adding at least 1.
2. Fertile Ground triggers, adding .
3. Activate Earthcraft by tapping Horseshoe Crab, untapping the basic land.
4. Activate Horseshoe Crab by paying , untapping it.
5. Repeat.
6. If the basic land is an Island, you may add mana of any color using Fertile Ground's trigger, and you may infinitely repeat steps 3-4 with any other basic land you control.

This elegant loop transforms simple mana generation into an infinite engine by exploiting the synergy between Earthcraft, Fertile Ground, and Horseshoe Crab. By using Earthcraft to tap Horseshoe Crab and untap a basic land enchanted with Fertile Ground, you generate extra mana from the land's triggered ability—enough to pay the activation cost needed to untap Horseshoe Crab and restart the cycle. Because Fertile Ground adds an additional mana of any color whenever that land is tapped for mana, this process quickly scales into infinite colored mana and infinite untaps of your basic lands.