Agatha's Soul Cauldron + Neerdiv, Devious Diver + North Pole Patrol

Agatha's Soul Cauldron

Neerdiv, Devious Diver

North Pole Patrol

How it works

1. Activate a creature using North Pole Patrol's ability by tapping it, untapping Neerdiv.
2. Activate Neerdiv using North Pole Patrol's ability by tapping it.
3. Neerdiv triggers, causing a player to mill cards equal to its power.
4. Resolve the Neerdiv ability from step 2, untapping another creature.
5. Repeat.

This ingenious loop centers around Agatha's Soul Cauldron, which acts as the magical vessel granting all the activated abilities of North Pole Patrol to creatures you control with +1/+1 counters on them—including Neerdiv, Devious Diver. By using North Pole Patrol's tap ability granted to Neerdiv, you can repeatedly untap the Patrol itself while utilizing Neerdiv's own tap ability to untap the Patrol right back, creating an endless loop of mutual activation. As this engine spins out of control, Neerdiv, Devious Diver triggers on each tap to mill away your opponent's library while growing ever stronger.