Barrenton Medic + Cathars' Crusade + Splinter Twin

RW identity

Commander legal

The 3 combo pieces

• Barrenton Medic
• Cathars' Crusade
• Splinter Twin

What must be in place

Splinter Twin attached to Barrenton Medic.
Barrenton Medic does not have summoning sickness.

How to execute it

1. Activate Barrenton Medic by tapping it, creating a token copy of it with haste.
2. When the Barrenton Medic token enters the battlefield, Cathars' Crusade triggers, putting a +1/+1 counter on each creature you control.
3. Activate the nontoken Barrenton Medic's second ability by putting a -1/-1 counter on it, untapping it.
4. Repeat.

What the combo produces

• Infinite +1/+1 counters on most creatures you control
• Infinite creature tokens with haste
• Infinite ETB