Rite of Passage + Conclave Mentor + Deathbringer Thoctar

Rite of Passage

Conclave Mentor

Deathbringer Thoctar

How it works

1. Activate Deathbringer Thoctar by removing a +1/+1 counter from it, dealing 1 damage to itself.
2. Rite of Passage triggers, putting two +1/+1 counters on Deathbringer Thoctar.
3. Repeat an arbitrarily large number of times.
4. Move to the next turn, removing all damage marked on Deathbringer Thoctar.
5. Activate Deathbringer Thoctar by removing a +1/+1 counter from it, dealing 1 damage to any target.
6. Repeat step 5 as desired.