When Adam fully transformed into a monkey, he threw his underpants in Jake's face and ran off naked.
When Jake came out of Adam's clothes, he took the clothes with him, revealing his underwear.
Adam proves how good his body looks, by stripping himself down to his underwear.
Adam splits his pants, revealing blue boxers with yellow stripes.
Adam undoes his pants and pulls them down, revealing his "Captain Clowny" underwear, and he honks the red nose on them, until Jake reminds him that he and Adam are "Live" on "Basic Jake."
Adam clone, A Unit outgrew it's clothes, sans his underwear for the sake of censorship.
Towards the end of the episode, Adam rips off his school uniform, revealing his underwear, and goes off to join all the animal students who have ripped their uniforms off, acting wild himself.
Adam sold his clothes to The Cuddlemuffins, aside from his underwear.
Adam gets spooked out of his clothes by Jake, demonstrating how humans can get scared by the littlest things and he lands in the bushes in his underwear. This leaves him to try to put his clothes on in the bushes, until Windsor Gorilla scares him out of the bushes, and then, hands Adam his clothes back to him.
In a flashback, Adam has come to school in his underwear, thinking it all to be just a dream; when in reality, it wasn't
Adam gives his clothes to the feral cats, so they can disguise as him and sneak into the school. This leaves Adam in his underwear, getting him kicked out of the school for violation of the dress code. He later runs through the library, singing "I Wanna Be An Airborne Ranger".
Adam is seen in his underwear in the beginning of the episode until he dons his normal clothes. Then, after Jake tries to get Adam to come with him to save Mrs. Warthog, he tears off Adam's clothes revealing his "Captain Clowny" uniform and underwear.
Jake gets scared of Bull and jumps into Adam's pants to hide. His underwear is briefly exposed, when he does.
Adam tears off his clothes, revealing his underwear. Then, he looks down and notices this, and becomes disappointed that he didn't wear his "Rhino" costume under his clothes today.
Adam's scrapbook included a picture of himself and Jake swapping clothes. Since Jake didn't wear pants, Adam was in his underwear. Then, earlier in the episode, Adam takes off his shirt, revealing his underwear, before he puts his clothes in the washing machine.
David Coppertrout revealed that Adam was now wearing Animal School Musical underwear.
At the beginning of the episode, Adam is the only student to get excited over the start of summer vacation, and he rips off his outer clothes, revealing his "Captain Clowny" underwear. Then, after he announces that he is going to "Captain Clowny Day Camp" for the summer, he turns around, honks the clown nose on the back of his "Captain Clowny" underwear, and then, does a little dance in them.