Basri's Lieutenant + Bloodspore Thrinax + Ashnod's Altar

Basri's Lieutenant

Bloodspore Thrinax

Ashnod's Altar

How it works

1. Activate Ashnod's Altar by sacrificing another creature with a +1/+1 counter on it, adding CC.
2. When the creature dies, Basri's Lieutenant's second ability triggers, creating a 2/2 Knight creature token that enters the battlefield with at least one +1/+1 counter due to Bloodspore Thrinax.
3. Repeat.

This clever loop turns the sacrifice outlet Ashnod's Altar into an infinite mana engine by exploiting the interaction between Basri's Lieutenant and Bloodspore Thrinax. Whenever you feed a creature to Ashnod's Altar, Basri's Lieutenant steps in with its death trigger to replace it with a fresh 2/2 Knight token. Thanks to Bloodspore Thrinax's continuous static ability, that token enters the battlefield already bearing a +1/+1 counter, which primes it to trigger Basri's Lieutenant all over again the moment you sacrifice it back to Ashnod's Altar.