Quickbeam, Upstart Ent + Devoted Druid + Ant Queen + Arcane Adaptation

Quickbeam, Upstart Ent

Devoted Druid

Ant Queen

Arcane Adaptation

How it works

1. Activate Devoted Druid's first ability by tapping it, adding .
2. Activate Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
3. Activate Devoted Druid's first ability by tapping it, adding .
4. Activate Ant Queen by paying 1, creating a 1/1 Insect creature token.
5. When the Insect enters the battlefield as a Treefolk due to Arcane Adaptation, Quickbeam triggers, giving Devoted Druid and up to one other creature +2/+2 until end of turn.
6. Activate Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
7. Repeat.

This clever loop relies on Arcane Adaptation to rewrite the very nature of your hive, turning every creature you control into a Treefolk. With that global type-shift active, each bug spawned by Ant Queen triggers Quickbeam, Upstart Ent to pump your board with massive buffs and trample. Meanwhile, the engine's eternal motion is fueled by Devoted Druid, whose ability to tap for green mana and untap by taking -1/-1 counters supplies both the necessary mana for the Queen and the raw untap momentum needed to sustain the cycle indefinitely.