Holding priority, cast Twincast by paying ({U} magic symbol) ({U} magic symbol) , creating a copy of Chandra's Ignition.
Kalamax first and second abilities triggers.
Resolve the first ability, creating a copy of Twincast.
Resolve the second ability, putting a +1/+1 counter on itself.
Resolve the Twincast copy, creating a copy of Twincast.
Repeat from step 3.
Once you have infinite copies of Twincast and arbitrarily large Kalamax, you may resolve Chandra's Ignition, dealing infinite damage to each other creature and each opponent.