Double Dennis

Double Dennis is the one hundred and twenty second episode from Season 1.

Plot
Dennis is skateboarding home to meet his cousin, who would be stopping by for a visit. Once Dennis arrives home, he unintentionally lands on Henry's back.

Dennis meets his aunt Judy, uncle Bob, and cousin Prentice, who looks exactly like Dennis in every way, except Prentice is much better behaved than his cousin. When their parents go inside, Dennis plans to show Prentice all kinds of stuff, except Prentice has to look at a new house with his parents. This gives Dennis a sneaky idea.

Dennis and Prentice swap outfits so that people will think Prentice is Dennis and vice versa. Dennis decides to look at a new house with his aunt and uncle, while Prentice meets Mr. Wilson.

As Prentice walks over to the Wilson place, he passes Margaret pushing a baby carriage with Molly in it. Margaret notices "Dennis", and tells him off for not greeting her and not to joke about her dolls. "Dennis" apologizes, says how lovely Margaret's dolls are, and that none of them are half as lovely as Margaret. Margaret, feeling loved, kisses "Dennis". "Dennis" continues off for the Wilson place, leaving Margaret with a loss for words that "Dennis" came to his senses.

Mr. Wilson is looking for a place to hang his mirror up when Prentice arrives. Mr. Wilson refuses "Dennis'" help with the mirror. Mr. Wilson accidentally trips over, shattering the mirror in the process. When Mrs. Wilson comes to the scene, Mr. Wilson explains about "Dennis" offering to help. Mrs. Wilson is making cookies, and "Dennis" offers to help with them, only for Mr. Wilson to intervene, and cause the dough to land on his head.

Meanwhile, Dennis is looking at a house with Judy and Bob, and he's messing around as usual. Dennis pulls the chain in the fireplace, causing soot to blow out of the fireplace. Bob explains to Judy that "Prentice" is developing her mother's traits.

When returning to the Mitchell place, Bob and Judy explain they decided not to buy the house since it was causing "Prentice" to behave like a menace. When "Prentice" comes back, he talks about how the suit is "like wearing a candy wrapper". Much to the surprise of Bob, Judy, Henry, and Alice, their sons had swapped outfits. Mr. Wilson then sees in disbelief "2 Dennises".

After Prentice and his parents leave, but not without swapping outfits back, Margaret comes up to Dennis. Still thinking he was the one who said kind words to her, Margaret kisses Dennis, only for Dennis to react in disgust and say nasty stuff to her, only for Margaret to realise it was "too good to be true! Talk about split personalities! Blecch!"