Alena, Kessig Trapper, and Umbral Mantle

Prerequisites

• Alena, Kessig Trapper on the battlefield
• Umbral Mantle on the battlefield
• Umbral Mantle attached to Alena
• Alena does not have summoning sickness
• A creature with power four or greater has entered the battlefield under your control this turn

Steps

1. Activate Alena by tapping it, adding at least
2. Activate Alena by paying and untapping it, giving it +2/+2 until end of turn
3. Repeat

Results

• Infinitely large Alena until end of turn
• Infinite red mana