Kentaro, the Smiling Cat + Shrieking Drake + Urza's Incubator + Conspiracy

Kentaro, the Smiling Cat

Shrieking Drake

Urza's Incubator

Conspiracy

How it works

1. Cast Shrieking Drake by paying 0.
2. When Shrieking Drake enters the battlefield, it triggers, returning itself from the battlefield to your hand.
3. Repeat.

This clever loop transforms Shrieking Drake into a zero-mana self-bouncing engine by turning it into a Samurai with the help of Conspiracy. Once Conspiracy names "Samurai," Kentaro, the Smiling Cat steps in to let you cast those Samurai spells by paying {X} rather than their mana cost, reducing the Drake's cost to literally nothing. To complete the cost reduction, Urza's Incubator can also be set to Samurai to shave generic mana off the spells, though Kentaro's alternative cost already makes the Drake free to endlessly recast and bounce itself.