Agatha's Soul Cauldron + Lurking Roper + Traveling Minister

Agatha's Soul Cauldron

Lurking Roper

Traveling Minister

How it works

1. Activate Lurking Roper using Traveling Minister's ability by tapping it, causing target creature to get +1/+0 until end of turn, and you to gain 1 life.
2. Lurking Roper triggers, untapping itself.
3. Repeat.

This clever loop turns minor life-gain into an infinite engine by feeding abilities through Agatha's Soul Cauldron. By exiling Traveling Minister into the Cauldron, its tap ability is granted to any creature you control with a +1/+1 counter on it—most notably Lurking Roper. Because Lurking Roper doesn't untap normally and untaps whenever you gain life, tapping it to use the Minister's ability both pumps a creature and triggers the Roper's untap condition simultaneously, creating a self-sustaining cycle of infinite life and infinitely large attackers.