Gravitic Punch + Kalamax, the Stormsire + Refuse // Cooperate

Gravitic Punch

Kalamax, the Stormsire

Refuse // Cooperate

How it works

1. Cast Gravitic Punch by paying its mana cost, targeting Kalamax.
2. Holding priority, cast Cooperate by paying its aftermath cost, targeting Gravitic Punch.
3. Kalamax's first and second abilities trigger.
4. Resolve the first ability, creating a copy of Cooperate targeting the original Cooperate.
5. Resolve the second ability, putting a +1/+1 counter on Kalamax.
6. Resolve the Cooperate copy, creating a copy of Cooperate, targeting the original Cooperate.
7. Kalamax's second ability triggers, putting a +1/+1 counter on itself.
8. Repeat from step 6 any number of times.
9. Once you have an arbitrarily large Kalamax, have the final Cooperate copy target Gravitic Punch. This'll create two copies of Gravitic Punch in addition to the original Gravitic Punch.
10. Resolve all Gravitic Punches, dealing infinite damage to each of up to three opponents.