Gravitic Punch, Kalamax, the Stormsire, and Return the Favor

Prerequisites

• Gravitic Punch in hand
• Kalamax, the Stormsire on the battlefield
• Return the Favor in hand
• available

Steps

1. Cast Gravitic Punch by paying its mana cost, targeting Kalamax
2. Holding priority, cast Return the Favor by paying plus an additional to select its first mode, targeting Gravitic Punch
3. Kalamax's first and second abilities trigger
4. Resolve the first ability, creating a copy of Return the Favor targeting the original Return the Favor
5. Resolve the second ability, putting a +1/+1 counter on Kalamax
6. Resolve the Return the Favor copy, creating a copy of Return the Favor, targeting the original Return the Favor
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 Return the Favor copy target Gravitic Punch
10. This'll create two copies of Gravitic Punch in addition to the original Gravitic Punch
11. Resolve all Gravitic Punches, dealing infinite damage to each of up to three opponents

Results

• Infinite magecraft triggers
• Infinite +1/+1 counters on a creature
• Infinite damage