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; the antidote consists of two teaspoons of applesauce, one cup of milk, three mashed bananas, and a dollop of 100% kona coffee. His one true place is at the dog shelter turning old dogs into adorable puppies, thus making them more appealing to potential adopters. Babyfier is voiced by Tara Strong.

Bio
Experiment 151 was the 151st genetic experiment created by Jumba with Hämsterviel's funding. He 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.

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.

Meanwhile, the babyfied Jumba (who still retained the intellect of adult Jumba) managed to find a cure on his computer that would reverse Babyfier's effects. Lilo despaired when she saw that one of the ingredients for the antidote was a dollop of 100% kona coffee, which only adults were allowed to buy.

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

Outside, Lilo tried coaxing a passing couple to buy her 100% kona coffee before Babyfier proceeded to turn the couple into babies. Lilo, the babyfied Nani, and the babyfied Stitch chased after Babyfier. Meanwhile, the babyfied Jumba and the babyfied Pleakley traveled to Kiki's Coffee Hut, where they managed to find several bags of 100% kona coffee on a shelf to make the remedy.

Later, the babyfied Stitch and Gantu tracked Babyfier down to a playground, where the two continually fought over him, with Stitch winning. After Babyfier was recaptured, Jumba and Pleakley (back to their original ages) 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, forcing the three experiments to retreat.

Leroy & Stitch
In the film's opening, Babyfier can be seen waving hello to Lilo, along with Snooty and Amnesio.

Later, the first 624 experiments, including Babyfier, were rounded 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 fail-safe.

Stitch! anime
Babyfier made an appearance in Season 2 of the Stitch! anime with Hammerface, Link, Spike, and Woody. He appeared again later where he left Stitch in charge of several schoolchildren that he turned into babies, including Yuna herself.

Personality
Babyfier is a nonchalant, babyish, mischievous baby morpher. He's mostly timid and is easily startled, which is not a good thing since this also triggers his regression spray as well.

Trivia

 * Babyfier's pod color is white.
 * Babyfier is described by the experiment computer screen as, "Experiment 151 Primary function: Infant maker. Change the victim into his infant form."
 * Babyfier's tail appears in the game Jumba's Lab.
 * Babyfier bears some resemblance to Mew from Pokemon, even having the same designation number, 151.
 * In the anime episode "Link-age," Reuben states that Babyfier's favorite type of sandwich is pureed carrots.