Babyfier

 Babyfier, A.K.A. Experiment 151, is an illegal genetic experiment created by Jumba Jookiba. He is designed to throw entire planets into chaos by turning the populance into babies. His one true place is turning old dogs at the dog shelter into more adoptable puppies. Babyfier is voiced by Tara Strong.

Bio
Experiment 151 was the 151st genetic experiment created by Jumba with Hämsterviel's funding. She was designed to turn entire civilizations into babies, throwing the planet into chaos.

151 and the other first 624 experiments were deactivated and smuggled to Earth by Jumba during his mission to capture Experiment 626.

All of the experiment pods were released and scattered across the island of Kauai, with 151's pod landing on a sidewalk.

Lilo & Stitch: The Series
When the Ice Cream Man tripped on 151's pod, it rolled across a nearby beach shore and into the ocean, activating 151, who proceeded to turn the tourist into a baby.

151 then went on a rampage, turning others, including a worker, into babies before Stitch was able to capture him.

Lilo and Stitch then took 151, named Babyfier, back to the house and learned about his powers.

That night, Stitch released Babyfier on Nani so that Lilo could be in charge for once. However, after turning Nani into a baby, Babyfier turned Stitch, Jumba and Pleakley into babies too. Babyfier attempted to turn Lilo into a baby as well, but was lured into a trap and recaptured.

Gantu, who had been searching for the experiment, arrived at the Pelekais' house the next day. Because Lilo's ohana was all babyfied and helpless, Gantu managed to take Babyfier back to his ship.

Meanwhile, the babyfied Jumba (who still retained the intellect of adult Jumba) searched his computer for a cure that would turn everyone back into adults. He then took the babyfied Pleakley along to help him collect the ingredients required to make the antidote.

When Experiment 625 discovered at Gantu's ship that Babyfier turns adults into babies, Reuben released Babyfier on Gantu. However, after turning Gantu into a baby, Babyfier attempted to do the same to Reuben, causing the latter to lock Babyfier out of the ship.

Babyfier went on a second rampage, turning countless victims throughout Kauai into babies.

The babyfied Stitch and Gantu tracked Babyfier down to a playground, where the two fought over him, with Stitch winning. Afterwards, Jumba and Pleakley (back to their older selves) arrived with the antidote. With Stitch's help, all the babies on Kauai were turned back into adults save Gantu.

Babyfier was then found a one true place turning old dogs at the dog shelter into adorable and more adoptable puppies, effectively giving them a second chance.

It is presumed that the babyfied Gantu was somehow turned back into his adult self.

In "Ploot," Babyfier was one of the second team of experiments (along with Finder and Drowsy) formed to try and stop Ploot. However, Ploot was easily able to defeat them.

Leroy & Stitch
The first 624 experiments, including Babyfier, were round up by Leroy and taken to a stadium to be destroyed. However, Lilo, Stitch, Jumba, Pleakley, Reuben and Gantu arrived before the experiments could be destroyed.

Babyfier participated in the following battle between the experiments and the Leroy clones by turning Leroys into babies.

However, the Leroys soon gained the upper hand in the battle, but were defeated when Lilo, Stitch, Reuben and several other experiments performed the song Aloha `Oe, which caused the Leroy army to shut down due to the original Leroy's failsafe.

Stitch! anime
Babyfier appeared in the Stitch! anime with Hammerface, Link, Spike, and Woody. He appeared again later where he left Stitch in charge of several school children that he turned into babies.