Necrotic Ooze, Auriok Bladewarden, and Barrenton Medic

Prerequisites

• Necrotic Ooze on the battlefield
• Auriok Bladewarden in the graveyard
• Barrenton Medic in the graveyard

Steps

1. Activate Necrotic Ooze using Auriok Bladewarden's ability by tapping it, giving it +X/+X until end of turn, where X is its power
2. Activate Necrotic Ooze using Barrenton Medic's second ability by putting a -1/-1 counter on it, untapping it
3. Repeat

Results

• Infinitely large Necrotic Ooze until end of turn