River Song + Conjurer's Bauble + Prototype Portal + Time Stretch

River Song

Conjurer's Bauble

Prototype Portal

Time Stretch

How it works

1. Activate Prototype Portal by paying 1 and tapping it, creating a token copy of Conjurer's Bauble.
2. Cast Time Stretch by paying 8, causing you to take two extra turns after this one.
3. Activate the Conjurer's Bauble token by tapping and sacrificing it, putting Time Stretch onto the bottom of your library from your graveyard, and then causing you to draw Time Stretch from the bottom of your library due to River Song.
4. Repeat each other turn.