That means if 2 frogs (middle and one outer) jumped, then the weight distribution of the last remaining outer frog would have been too much, therefore tipping the lily pad off balance and throwing the remaining frog into the water. That was the easy explanation.
Medusa first appeared in Fantastic Four #36 (1965), and was created by Stan Lee and Jack Kirby. She appears first in flashback, then in costume as part of the fledgling Frightful Four. She appears in #38, 41, 42, 43, 44-48 and in various subplot glimpses from #49-62. The Inhumans also appear in Fantastic Four # 82-83, with Medusa.
In Greek mythology Perseus was a hero who was said to have founded the ancient city of Mycenae. He killed Medusa, who was so ugly that anyone who gazed upon her was turned to stone, by looking at her in the reflection of his shield and slaying her in her sleep.