River Song + Conjurer's Bauble + Prototype Portal + Walk the Aeons

River Song

Conjurer's Bauble

Prototype Portal

Walk the Aeons

How it works

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