Crystalline Crawler, Saving Grace, Vigor, and Pestilence Demon

Prerequisites

• Crystalline Crawler on the battlefield
• Saving Grace in hand
• Vigor on the battlefield
• Pestilence Demon on the battlefield
• available

Steps

1. Cast Saving Grace by paying , targeting Crystalline Crawler
2. Saving Grace enters the battlefield and triggers, causing all damage that would be dealt to you and to permanents you control this turn to be dealt to Crystalline Crawler instead
3. Activate Pestilence Demon by paying , dealing 1 damage to each opponent and each creature they control, and attempting to deal 1 damage to you and each creature you control
4. Saving Grace redirects that damage to Crystalline Crawler
5. Vigor's replacement effect prevents that damage and puts that many +1/+1 counters on Crystalline Crawler instead
6. Activate Crystalline Crawler's first activated ability by removing a +1/+1 counter, adding
7. Repeat from step 3

Results

• Infinite +1/+1 counters on Crystalline Crawler
• Infinite colored mana
• Infinite damage to opponents and each creature your opponents control