Crackdown Construct, Cryptolith Rite, and Horseshoe Crab

Prerequisites

• Crackdown Construct on the battlefield
• Cryptolith Rite on the battlefield
• Horseshoe Crab on the battlefield
• Horseshoe Crab does not have summoning sickness

Steps

1. Activate Horseshoe Crab by tapping it, adding
2. Activate Horseshoe Crab by paying
3. Crackdown Construct triggers, giving itself +1/+1 until end of turn
4. Resolve the Horseshoe Crab ability, untapping it
5. Repeat

Results

• Infinitely large Crackdown Construct until end of turn