Requires

Lagrella, the Magpie must be on the battlefield. Karmic Guide must be on the battlefield. Preston, the Vanisher must be on the battlefield. Momentary Blink must be in hand. Mana needed:

Steps

1. Cast Momentary Blink by paying , blinking Lagrella.
2. When Lagrella enters the battlefield, it and Preston triggers.
3. Resolve the Lagrella trigger, exiling Karmic Guide until Lagrella leaves the battlefield.
4. Resolve the Preston trigger, creating a token copy of Lagrella that is a 0/1 Illusion.
5. Put the nontoken Lagrella into your graveyard due to the legend rule.
6. If Lagrella is your commander, choose not to return it to the command zone from your graveyard.
7. When Lagrella leaves the battlefield, Karmic Guide is returned to the battlefield from exile.
8. Karmic Guide, Lagrella and Preston each trigger.
9. Resolve the Preston trigger, creating a token copy of Karmic Guide that is a 0/1 Illusion.
10. When the Karmic Guide token enters the battlefield, it triggers, choosing to return nothing to the battlefield.
11. Resolve the Lagrella trigger, putting two +1/+1 counters on the nontoken Karmic Guide.
12. Resolve the Karmic Guide trigger from step 8, returning Lagrella from your graveyard to the battlefield.
13. Repeat from step 2.

Results