Tortured Existence + Pitiless Plunderer + Insidious Roots + Phantom Train

Tortured Existence

Pitiless Plunderer

Insidious Roots

Phantom Train

How it works

1. Activate Tortured Existence by paying and discarding a creature card, returning another creature card from your graveyard to your hand.
2. Insidious Roots triggers, creating a creature token and putting a +1/+1 counter on each Plant you control
3. Activate Phantom Train by sacrificing the creature token.
4. When the creature token dies, Pitiless Plunderer triggers, creating a Treasure token.
5. Resolve the Phantom Train ability.
6. Activate a Treasure by tapping and sacrificing it, adding .
7. Repeat.

This clever engine loops creatures back and forth through your graveyard using Tortured Existence while fueling itself entirely from within. Every time you swap a creature, Insidious Roots notices the card leaving your graveyard to spawn a Plant token and pump your team. You can then feed that token to Phantom Train, whose activation triggers Pitiless Plunderer to generate a Treasure token. Cracking that Treasure refunds the black mana needed to keep Tortured Existence running, leaving you with an unstoppable loop of sacrifices and triggers.