Super Smash Bros. isn't the series being invaded by babies and dead versions of people.
I do like Dry Bones, however. I think of him as the Koopa Troopa from Super Mario Kart, while the Koopa from Double Dash and Mario Kart Wii (and probably playable in some parties) is a newcomer.
And, Baby Luigi isn't dancing with Baby Daisy. He's trying to prevent the terrible future by throwing her around. But that might be why Daisy's so messed up...