Shaile, Dean of Radiance // Embrose, Dean of Shadow, Crystalline Crawler, Cryptic Trilobite, and Umbral Mantle

Prerequisites

• Shaile, Dean of Radiance // Embrose, Dean of Shadow on the battlefield
• Crystalline Crawler in hand
• Cryptic Trilobite in hand
• Umbral Mantle on the battlefield
• Shaile does not have summoning sickness
• Umbral Mantle attached to Shaile
• available

Steps

1. Cast Crystalline Crawler by paying
2. Cast Cryptic Trilobite by paying
3. Activate Shaile by tapping it, putting a +1/+1 counter on Crystalline Crawler, Cryptic Trilobite and any other creature that entered the battlefield under your control this turn
4. Activate Crystalline Crawler's first ability by removing a +1/+1 counter from it, adding
5. Activate Cryptic Trilobite's first ability by removing a +1/+1 counter from it, adding that can only be spent to activate abilities
6. Activate Shaile by paying and untapping it, giving it +2/+2 until end of turn
7. Repeat from step 3

Results

• Infinite +1/+1 counters on other creatures you control that entered the battlefield this turn
• Infinitely large Shaile until end of turn