Rite of Passage + Triskelion + Hardened Scales

Rite of Passage

Triskelion

Hardened Scales

How it works

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