Sensei's Divining Top + Skyswimmer Koi + Gran-Gran

Sensei's Divining Top

Skyswimmer Koi

Gran-Gran

How it works

1. Cast Sensei's Divining Top by paying 0 due to Gran-Gran.
2. When Sensei's Divining Top enters, Skyswimmer Koi triggers.
3. Holding priority, activate Sensei's Divining Top by tapping it, causing you to draw a card and put Sensei's Divining Top on top of your library.
4. Resolve the Skyswimmer Koi trigger, causing you to draw Sensei's Divining Top from your library, and then discard a card other than Sensei's Divining Top.
5. Repeat

This clever loop transforms a humble artifact into a relentless mechanical engine by exploiting the interaction between the top of your library and your hand. Gran-Gran provides the crucial cost reduction that makes Sensei's Divining Top free to cast, meaning every iteration costs zero mana. As the Top enters, Skyswimmer Koi triggers to let you loot, and by floating a tap-activation of the Top in response, you can intercept the draw effect to put the Top right back into your hand instead of letting it hit the graveyard. This lets you endlessly recast and redraw Sensei's Divining Top while churning through your entire deck, triggering Skyswimmer Koi on every single pass.