Crackdown Construct, and Shaman en-Kor

Prerequisites

• Crackdown Construct on the battlefield
• Shaman en-Kor on the battlefield

Steps

1. Activate Shaman en-Kor's 0 mana ability targeting a creature you control
2. Crackdown Construct gets +1/+1 until end of turn
3. Repeat

Results

• Infinitely large Crackdown Construct