Agatha's Soul Cauldron, Phyrexian Devourer, and Giggling Skitterspike

Prerequisites

• Agatha's Soul Cauldron on the battlefield
• Phyrexian Devourer in exile
• Giggling Skitterspike on the battlefield

Steps

1. Activate Giggling Skitterspike using Phyrexian Devourer by exiling the top card of your library, putting a number of +1/+1 counters on Giggling Skitterspike equal to the card's mana value
2. Repeat step 1 as desired
3. Declare Giggling Skitterspike as an attacker, triggering its ability, dealing damage equal to its power to each opponent

Results

• Exile your library
• Near-infinite +1/+1 counters on a creature
• Near-infinite damage