Star Trek's rip-off of the Martian flat cats from Robert A. Heinlein's The Rolling Stones.

Heinlein's book, published in 1952, featured an encounter between the Stone family and a species of fuzzy, purring, ever-hungry, ever-breeding beasties known as flat cats. While stopping at Mars en route to the Asteroid Belt, the teenage Stone twins picked up a flat cat as a pet. When they discovered that, given food, it would breed, they thought to sell the pleasantly-buzzing critters to Belter miners as pets. Soon, however, the expanding fuzzball population threatened the food supply on the family's spaceship, and they were forced to stuff the "pets" into a hold and freeze them all into hibernation.