One of the saddest fates that can befall a cartoon or comics character is when, in an attempt to revive a "franchise" or push merchandise or follow a trend, they are fundamentally altered, most often by just switching their ages. Juvenilization is seldom pretty, and it's often seen as a 1980s thing (Muppet Babies was quite the hit). As far as I'm aware, however, the earliest example, discounting one-shot cartoons where Bugs or Woody Woodpecker become babies or flashback, is Little Archie. The main reason Little Archie, at its best, holds up is because it had a kind of logical basis (even if it had to skip continuity issues and assume that Veronica has always lived in Riverdale), it added new characters, and frankly it was more open about the often harsh nature of childhood than the wholesome scrubbed teen Archie stories were (in particular, Archie and Jughead, the "good" guys, routinely joining Reggie to humiliate, exploit, or pummel picked-on classmate Ambrose).
These approaches generally homogenize characters and simplify their personalities. It hasn't died out, alas, as Baby Looney Tunes attests. It can become even weirder, however, when the characters in question have already been stripped of most or all of their gumption, as with Mickey Mouse in the 1980s, when the "Disney Babies" first surfaced. They still appear on and off, and serve only to fulfill a "Look how cute" function, in a world where the Disney Babies (actually called that in one book) have no discernible personalities whatsoever outside of being cute and nice and emotionally fragile.
And this was worse when they went beyond Mickey, Minnie, Goofy, et., in search of more characters. To wit, gaze at the image below:
At least Baby Horace retained his collar (this book, picked up for sixty cents, has Horace missing his blanket, but he's quickly comforted when his newfound daycare pals let him use the daycare's teddy bear. The end.) While revivals of Horace and Clarabelle are generally a good thing, this is just sad.
Moments ago, I took a closer look at the endpapers, however, and found this, which is even worse:
No doubt somewhere out there, they also have an infant Phantom Blot (the shy Blotty, who feels self-conscious because he looks different) or a Baby Scrooge (Booge?) who likes money only because it's shiny. Sheesh. (This is still less disturbing than that Baby Popeye image that circulated awhile back, though, with a teeny tiny Baby Baby Swea'pea hung around Baby Olive's neck).