Devoted Druid + Leyline of Abundance + Branching Evolution + Benevolent Hydra

Devoted Druid

Leyline of Abundance

Branching Evolution

Benevolent Hydra

How it works

1. Activate Leyline of Abundance by paying 6, putting four +1/+1 counters on each creature you control due to Benevolent Hydra and Branching Evolution.
2. Activate Devoted Druid's first ability by tapping it, adding .
3. Leyline of Abundance triggers, adding .
4. Activate Devoted Druid's second ability by putting a -1/-1 counter on it, untapping Devoted Druid.
5. Repeat from step 2 three additional times.
6. Repeat from step 1.

This clever loop lets you turn an initial mana investment into infinitely large creatures by exploiting the interplay between counters and mana production. With Leyline of Abundance on the battlefield, tapping Devoted Druid for green mana produces extra mana, which you can use to activate Leyline's massive pump ability—a cost made even more potent because Benevolent Hydra and Branching Evolution dramatically multiply the incoming +1/+1 counters. Each cycle of placing counters cancels out the -1/-1 counters Devoted Druid uses to untap itself, leaving your druid fully operational and your entire board infinitely growing with every iteration.