Sole Brother is the third part of the 1st episode in Season 3 of Dexter's Laboratory, with the episode first appearing on November 16, 2001. In this episode, a teleportation mishap in Dexter's laboratory causes Dexter to become Dee Dee's foot. As a result, he and Dee Dee have to wait an entire day to reverse the effects.
Dexter is in his lab testing out his new teleporter using an apple as his test subject. The test proves to be a success, and Dexter eats it. Dexter prepares to teleport himself, but couldn't due to low power. On the next day, Dexter tries to teleport himself, but is halted by an error in the second teleporter. Computer alerts him, but Dexter ignores it and the test proceeds as normal. The teleportation, while a success, ends with Dexter being part of Dee Dee's foot. Dexter struggles to get free, but Dee Dee starts moving and slamming Dexter's face into the ground.
Dee Dee looks at her brother as her foot, and she tries to shake Dexter off. Dexter accuses Dee Dee of ruining the experiment, and explains the consequences to her. Mom calls Dexter and Dee Dee down for lunch and come up with a plan to avoid having Mom know about the dilemma. Back in the lab, Dexter again suggests about hiding out for the rest of the day, only for Dee Dee to realize she's late for her dance auditions. After the auditions, Dee Dee heads back inside the house and purposefully stomps her brother's face into the floor. Dad calls for Dee Dee, which gives her an opportunity to tell him about Dexter's lab. Dad tells Dee Dee that her dance audition went over well. Dee Dee decides to call it a day and heads to bed.
After 24 hours have passed, Dexter and Dee Dee go into Dexter's lab to reverse the effects. The test was a success, but Dee Dee has wings and Dexter has a stinger. They both go their own ways while the bug stands there and does a dance.
The episode was originally going to include a scene in which Dexter and Dee Dee were in dance class, but was removed for time.
For reasons unknown, the sound effects for the Hanna-Barbera logo used throughout Season 2 of the series (as well as for other Hanna-Barbera-produced Cartoon Cartoons of 1997 such as Johnny Bravo (season 1 only), Cow and Chicken and I Am Weasel) play over the Cartoon Network Studios logo. This is fixed in subsequent episodes.
The episode's title may be a reference to the 1957 album Soul Brothers.