Glare of Subdual, Solitary Sanctuary, and Barrenton Medic

Prerequisites

• Glare of Subdual on the battlefield
• Solitary Sanctuary on the battlefield
• Barrenton Medic on the battlefield

Steps

1. Activate Glare of Subdual by tapping Barrenton Medic, tapping a creature an opponent controls
2. Solitary Sanctuary triggers, putting a +1/+1 counter on Barrenton Medic
3. Activate Barrenton Medic's second ability by putting a -1/-1 counter on it, untapping it
4. Repeat as desired

Results

• Tap all creatures opponents control during each turn