Agatha's Soul Cauldron + Kiki-Jiki, Mirror Breaker + Lurking Roper + Healer of the Pride

Agatha's Soul Cauldron

Kiki-Jiki, Mirror Breaker

Lurking Roper

Healer of the Pride

How it works

1. Activate Lurking Roper using Kiki-Jiki's ability by tapping it, creating a token copy of itself with haste.
2. When the Lurking Roper token enters the battlefield, Healer of the Pride triggers, causing you to gain 2 life.
3. Each Lurking Roper you control triggers, untapping themselves.
4. Repeat.
5. You may also target any nonlegendary creature you control.

Agatha's Soul Cauldron serves as the clever glue of this engine, allowing a creature exiled within it to grant its activated abilities to anything bearing a +1/+1 counter—in this case, feeding Kiki-Jiki, Mirror Breaker's legendary-copying gifts directly to a nonlegendary creature like Lurking Roper. Once Lurking Roper gains that tap ability, tapping it to copy itself brings a Healer of the Pride onto the battlefield. That new entry immediately triggers Healer of the Pride to grant you life, which in turn causes the Lurking Ropers to untap themselves, leaving you free to repeat the loop indefinitely for an unstoppable swarm of hasty copies, life, and triggers.