Traveling Plague + Spawning Pit + Siona, Captain of the Pyleas

Traveling Plague

Spawning Pit

Siona, Captain of the Pyleas

How it works

1. Cast Traveling Plague by paying 3, attaching it to another creature you control.
2. When Traveling Plague enters, Siona triggers, creating a creature token.
3. Activate Spawning Pit by sacrificing the creature Traveling Plague is attached to.
4. When the creature dies, Traveling Plague triggers, returning itself from your graveyard to the battlefield attached to the token created in step 2.
5. When Traveling Plague enters, Siona triggers, creating a creature token.
6. Resolve the Spawning Pit ability.
7. Repeat from step 3.