Rite of Passage | Walking Ballista | Copy Enchantment

Cards

All permanents on the battlefield (
Walking Ballista with three or more +1/+1 counters on it and
Copy Enchantment as a copy of
Rite of Passage).

Activate
Walking Ballista by removing a +1/+1 counter from it, dealing 1 damage to itself.
Rite of Passage and
Copy Enchantment trigger, putting two +1/+1 counters on
Walking Ballista.
Repeat an arbitrarily large number of times.
Move to the next turn, removing all damage marked on
Walking Ballista.
Activate
Walking Ballista by removing a +1/+1 counter from it, dealing 1 damage to any target.
Repeat step 5 as desired.