Activate Mystic Sanctuary and The Eternity Elevator by tapping them, adding CCC.
Cast Ghostly Flicker either from your hand or from the top of your library by paying 2, blinking Mystic Sanctuary and The Eternity Elevator.
When Mystic Sanctuary enters untapped, it triggers, putting Ghostly Flicker from your graveyard onto the top of your library.
Repeat.
This mesmerizing engine is fueled by The Eternity Elevator, which taps to generate the initial colorless mana needed to get things rolling alongside Mystic Sanctuary's blue source. By casting Ghostly Flicker, you exile both lands and return them straight back to the battlefield, a loop made seamless by the top-of-library casting permissions granted by One with the Multiverse. Every time Mystic Sanctuary enters the battlefield untapped, its triggered ability returns Ghostly Flicker right back to the top of your library so you can play it again.