Marvin, Murderous Mimic, Farmstead Gleaner, and Gyre Engineer

Prerequisites

• Marvin, Murderous Mimic on the battlefield
• Farmstead Gleaner on the battlefield
• Gyre Engineer on the battlefield

Steps

1. Activate Marvin using Gyre Engineer's ability by tapping it, adding
2. Activate Marvin using Farmstead Gleaner's ability by paying and untapping it, putting a +1/+1 counter on Marvin
3. Repeat

Results

• Infinite +1/+1 counters on a creature