Mossborn Hydra, Agatha's Soul Cauldron, Fertilid, and Crystalline Crawler

Prerequisites

• Mossborn Hydra on the battlefield
• Agatha's Soul Cauldron on the battlefield
• Fertilid in exile
• Crystalline Crawler in exile
• Mossborn Hydra has at least four +1/+1 counters on it
• available

Steps

1. Activate Mossborn Hydra using Fertilid's ability by paying and removing a +1/+1 counter from it, causing you to search your library for a basic land card and put it onto the battlefield tapped
2. When the land enters the battlefield, Mossborn Hydra triggers, doubling the number of +1/+1 counters on it
3. Activate Mossborn Hydra twice using Crystalline Crawler's first ability by removing two +1/+1 counters from it, adding
4. Repeat until there are no basic lands in your library

Results

• Near-infinite colored mana
• Put all basic land cards from your library onto the battlefield tapped
• Near-infinite +1/+1 counters on Mossborn Hydra