Phyrexian Devourer, and Beacon of Tomorrows

Prerequisites

• Phyrexian Devourer on the battlefield
• Beacon of Tomorrows in hand
• each turn available

Steps

1. Activate Phyrexian Devourer by exiling the top card of your library
2. Repeat step 1 until you have an empty library
3. Resolve the first Phyrexian Devourer ability, putting a number of +1/+1 counters on it
4. If Phyrexian Devourer's power is at least seven, it triggers, causing you to sacrifice it
5. Repeat from step 3 for each remaining trigger
6. Cast Beacon of Tomorrows by paying , causing you to take an extra turn after this one and shuffle it into your library
7. Move to your next turn, drawing Beacon of Tomorrows from your library
8. Repeat from step 6

Results

• Exile your library
• Infinite turns
• Skip your draw step