Crackdown Construct, Cryptolith Rite, and Torchling

Prerequisites

• Crackdown Construct on the battlefield
• Cryptolith Rite on the battlefield
• Torchling on the battlefield

Steps

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

Results

• Infinitely large Crackdown Construct until end of turn