Mikaeus, the Unhallowed + Putrid Goblin + Phantom Train

Mikaeus, the Unhallowed

Putrid Goblin

Phantom Train

How it works

1. Activate Phantom Train by sacrificing Putrid Goblin.
2. When Putrid Goblin dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Resolve the Phantom Train ability.
4. Activate Phantom Train by sacrificing Putrid Goblin.
5. When Putrid Goblin dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
6. Resolve the Phantom Train ability.
7. Repeat.

This cunning loop uses Mikaeus, the Unhallowed to stitch together a self-sustaining engine of resurrection, leveraging his static lord ability to grant undying to other non-Human creatures. Putrid Goblin serves as the expendable heart of the operation, balancing its native persist ability against Mikaeus's undying to continually wipe away opposing counter types through repeated deaths. Meanwhile, Phantom Train acts as the catalyst that feeds the goblin to its hungry engine, converting each sacrifice into a growing mountain of +1/+1 counters on the Vehicle itself while keeping the recursion churning indefinitely.