When Weasel and Baboon have their brains switched, their voices change as well. Rather than merely swapping voice actors, Charlie Adler continues to voice I.R. Baboon, but doing an imitation of I.M. Weasel's voice. Additionally, Michael Dorn imitates I.R. Baboon's voice when voicing Weasel with Baboon's brain.
The reason Weasel and Baboon ended up with the others brain is because the doctors that operated on them were ignorant and believed that the size of their had matched the size of their brains.
We learn that Baboon has a sister named Barbie.
Baboon gets married in this episode, yet in the next episode he isn't anymore.
In this episode, when Weasel is seen without his fur, he looks like a little human with a big weasel nose and a tail. However, in later episodes when Weasel strips of his fur, he looks like his normal weasel-like shape but without the fur.
The Queen of Yurp's scepter is a plunger.
This is the first time the Kingdom of Yurp is seen.
Reference-When I.R. Baboon sticks banana peels in I.M. Weasel's Rocket and then proceeding to blow up, it is in slight reference to the Challengerexplosion that happened exactly 11 years, 6 months and 6 days from the episode's first airing.
Goof: Despite saying the mission was set at night, it is actually the afternoon as the sky was blue.