Activate Mesmeric Trance by paying and discarding a card.
The discarded card is exiled instead of being put into your graveyard due to Rest in Peace.
Ranar triggers, creating a 1/1 Spirit creature token.
Resolve the Mesmeric Trance ability, causing you to draw a card.
Activate Phyrexian Altar by sacrificing the Spirit, adding .
Repeat.
This clever loop turns your discard outlet into a self-sustaining engine by redirecting your graveyard into the ether. With Rest in Peace rewriting the rules so that any card put into a graveyard is exiled instead, filtering your cards through Mesmeric Trance becomes the catalyst for Ranar the Ever-Watchful to continuously spawn flying Spirit tokens. You can then feed those very tokens right into Phyrexian Altar to generate the blue mana needed to keep activating Mesmeric Trance over and over again.