Enduring Renewal + Workhorse + Shang-Chi, Martial Mentor

Enduring Renewal

Workhorse

Shang-Chi, Martial Mentor

How it works

1. Cast Workhorse by paying 6, causing it to enter the battlefield with eight +1/+1 counters on it due to [[Increaser - +1/+1 Counters]].
2. Activate Workhorse by removing a +1/+1 counter from it, adding C.
3. Repeat step 2 until Workhorse has no +1/+1 counters on it.
4. Workhorse dies as a state-based action due to having 0 toughness, triggering Enduring Renewal, returning Workhorse from your graveyard to your hand.
5. Repeat.