Future Kittens are kittens that haven't been born yet. However, they're still adorable.
They are generaly described as little floating balls of fuzz with ears and whiskers. They float around in the infinite abys of not being born yet until they are ready to be loved.
"Future kittens, future kittens. Haven't been born yet but their still adorable."
"mew mew mew... maaooo"
"Tyler Durden is a future kitten!"