Lazav, the Multifarious + Safehold Elite + Ashnod's Altar + Nardole, Resourceful Cyborg

Lazav, the Multifarious

Safehold Elite

Ashnod's Altar

Nardole, Resourceful Cyborg

How it works

1. Activate Lazav by paying 2, choosing to have it become a copy of Safehold Elite if it doesn't have a -1/-1 counter on it, or Nardole otherwise.
2. Activate Ashnod's Altar by sacrificing Lazav, adding CC.
3. When Lazav dies, if it was a copy of Safehold Elite, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
4. Otherwise, Lazav's undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
5. When Lazav enters the battlefield, it triggers, causing you to surveil 1.
6. Repeat.

This clever loop turns the shape-shifting shapeshifter Lazav, the Multifarious into an endless engine of sacrifice by pivoting between two key identities. When Nardole, Resourceful Cyborg has built up a +1/+1 counter and died, you can pay into Lazav to become a copy of Safehold Elite; because Safehold Elite's persist ability brings it back with a -1/-1 counter, those opposing counters instantly cancel each other out. This leaves Lazav clean and ready to become a copy of Nardole, Resourceful Cyborg instead, whose undying ability will return it with a +1/+1 counter when sacrificed to Ashnod's Altar. By feeding the resulting colorless mana back into Lazav's activation cost, you loop these two mechanics infinitely while Ashnod's Altar converts your eternal cycle into a mountain of mana and endless surveil triggers.