Roving Actuator + Displacer Kitten + Pull from Eternity + The Mirari Conjecture

Roving Actuator

Displacer Kitten

Pull from Eternity

The Mirari Conjecture

How it works

1. Cast Roving Actuator by paying 3.
2. When Roving Actuator enters the battlefield, it triggers, exiling Pull from Eternity from your graveyard, and then copying it and casting the copy without paying its mana cost, targeting any card you own in exile.
3. Displacer Kitten and The Mirari Conjecture trigger, with Displacer Kitten targeting Roving Actuator.
4. Resolve the The Mirari Conjecture trigger, copying the Pull from Eternity spell, targeting the original Pull from Eternity.
5. Resolve the copy of the Pull from Eternity Spell from step 4, putting Pull from Eternity from exile into your graveyard.
6. Resolve the Displacer Kitten trigger, blinking Roving Actuator.
7. Repeat from step 2.

This intricate loop hinges on an infinite recursion of entering and leaving the battlefield, anchored by Roving Actuator triggering off a prior nonland permanent leaving. Each time Roving Actuator enters, its ability snatches Pull from Eternity from your graveyard to exile a card and cast a free copy, while Displacer Kitten ensures Roving Actuator blinks away and resets whenever you cast that noncreature spell. Meanwhile, The Mirari Conjecture sits patiently on Chapter III to double your spells, allowing a copied Pull from Eternity to retrieve the original card from exile and send it straight back to your graveyard to fuel the next iteration.