Prototype Portal + Dross Scorpion + Myr Moonvessel + Bartolomé del Presidio

Prototype Portal

Dross Scorpion

Myr Moonvessel

Bartolomé del Presidio

How it works

1. Activate Prototype Portal by paying 1 and tapping it, creating a token copy of Myr Moonvessel.
2. Activate Bartolomé del Presidio by sacrificing Myr Moonvessel.
3. When Myr Moonvessel dies, Myr Moonvessel and Dross Scorpion trigger.
4. Resolve the Myr Moonvessel trigger, adding C.
5. Resolve the Dross Scorpion trigger, untapping Prototype Portal.
6. Resolve the Bartolomé del Presidio ability, putting a +1/+1 counter on it.
7. Repeat.