Big Baby

Big Baby is the one hundred and ninth episode from Season 1.

Plot
Dennis has arrived home, only to hear that Alice is in the kitchen, babysitting a baby named Sylvester, who is the son of Mrs. Atkins. As Dennis sees that Alice is using strained vegetables to feed Sylvester, he says Sylvester has a lot to learn, only to be proven correct when Sylvester blows raspberry and throws the tablespoon. Because that was the last of his food, Alice rushes to the shop to buy some more, trusting Sylvester in Dennis' hands. Dennis wonders what bad could happen within the time Alice leaves to the time Alice comes home.

Dennis spoke too soon, as PeeBee has arrived with a baby bottle, containing a formula that grows things to an enormous size. Dennis introduces PeeBee to Sylvester, and PeeBee wants something to experiment on with his formula. First, Dennis allows PeeBee to experiment with a pea. Dennis starts to question PeeBee keeping the formula in a baby bottle, and PeeBee explains that only one drop of the formula is needed to grow. The formula works, as the pea grows to the size of a basketball, and Dennis bounces it around like one, saying he feels like one of the Harlem Peatrotters. Dennis throws the giant pea to PeeBee, only for the giant pea to break to pieces.

Nevertheless, PeeBee decides to try another pea with the formula. However, when PeeBee tries a different pea, nothing happens because he used baby's formula, which could only mean one thing.... Sylvester drank almost all the growth formula, and he's grown super-sized. Dennis and PeeBee find him outside playing with a wheelbarrow like a toy. Dennis and PeeBee need to act fast because Alice would be home in a few minutes. PeeBee rushes home to invent an anti-growth formula.

Dennis runs after Sylvester, who is crawling along and playing with a real car like a toy car, causing traffic problems. Dennis calls Sylvester bad, only for Sylvester to cry tears large enough to make it rain. Luckily, Dennis has an umbrella. He gets one and forgives Sylvester. He was shrinking back to a normal size while crying. Next, Sylvester takes out a streetlamp, impressing Dennis.

Later, Sylvester crawls to the city's water supply and drinks it all. Dennis figures out a way to get Sylvester back to the Mitchell place, and then it hit him; Kids love candy. Dennis takes out some jellybeans and some of PeeBee's remaining growth formula. Dennis uses the formula to grow the jellybeans, and leaves a trail for Sylvester to eat along the way. Dennis succeeds in getting Sylvester home, and wonders where PeeBee is with the antidote. At this moment, PeeBee comes back with the antidote, but had no time to test it.

Sylvester takes the antidote, drinks it, and..... nothing happens. Suddenly, Alice arrives home with the food. Dennis rushes in, blocks the door, and Alice wonders where Sylvester is. Alice sees Dennis' suspicions, only for Dennis to cave in and open the door. Much to Dennis' surprise, Sylvester shrunk back to his normal size, and PeeBee is playing with him. Alice was afraid that Sylvester would turn into a big problem, only for Dennis to wink.

Trivia

 * The theme tune to The Littles plays in the background when Dennis agrees to look after Sylvester.
 * The Harlem Peatrotters is a pun on the NBA team The Harlem Globetrotters.
 * Dennis breaks the fourth wall at the end by winking at the audience.