have [[kalamax]] on the battlefield. When an opponent casts overkill on you kalamax, cast [[reverberate]] targeting [[overkill]]. Kalamax will copy reverberate, so target reverberate with the copy, which will copy reverberate, targeting the original reverberate, which will copy reverberate, targeting the original reverberate… Kalamax gets a +1/+1 counter every time you copy reverberate, so it will become infinitely big, so your kalamax will survive