The best thing to come out of "The Alternative Factor", many years later, was the audio birthday card, which I've seen two versions of:
[Picture of Kirk and Spock on front of card with text that reads:]
"Mr. Spock, what would happen if we were to light all the candles on that birthday cake at once?"
[Open card to hear sound bite of Spock saying:]
"Annihilation, Jim...total, complete, absolute annihilation."
[Quoted from memory.]