Falco Spara, Pactweaver + Sensei's Divining Top + Stone Calendar + Medusa, Inhuman Queen

Falco Spara, Pactweaver

Sensei's Divining Top

Stone Calendar

Medusa, Inhuman Queen

How it works

1. Activate Sensei's Divining Top's second ability by tapping it, causing you to draw a card and put Sensei's Divining Top on top of your library.
2. Cast Sensei's Divining Top by paying 0 and removing a counter from a creature you control.
3. Medusa triggers, putting a +1/+1 counter on it.
4. Repeat.

This brilliant loop relies on Falco Spara, Pactweaver to let you cast spells directly from the top of your library by trading away creature counters instead of paying mana. Stone Calendar smoothly reduces the cost of Sensei's Divining Top down to zero, allowing you to continually tap it to draw a card and place itself back on top of your library. Whenever you recast it for free, Medusa, Inhuman Queen happily triggers off the noncreature spell to replenish your fodder by placing a brand new +1/+1 counter back onto herself.