The Really Cool Adventures of Captain Underpants is a comic by Treehouse Comix, Inc., written by George Beard and illustrated by Harold Hutchins. This seems to be the first in the series. It appears in The Adventures of Captain Underpants. George and Harold were selling copies of this on the playground for 50 cents each. This comic doesn't serve much purpose in the book. it was shown in as opposed to most of the other comics shown in the series. However this book indirectly made Mr. Krupp so angry that he vowed to get George and Harold one day and thus motivated him to find a way to catch George and Harold in the act of one of their pranks.
The comic in the book starts with the Earth in a time of darkness and despair. Bad guys have taken over the world, while all the superheroes (including Superman, Captain America and Batman) in the world are too old to fight them. Captain Underpants suddenly appears as a new extra-strength superhero, and the introduction comes in explaining that he is "faster than a speeding waistband", "more powerful than boxer shorts", and is "able to leap tall buildings without getting a wedgie". Night and day, he fights for truth, justice "and all that is pre-shrunk and cottony".
Meanwhile, at a nearby school, the cafeteria gives the children the "Stinky Taco Surprise" since it is "Stinky Taco Surprise Day" at the timing. The children throw it all away since they hate it so much. The wasted food then comes to life as the Inedible Hunk (a parody of The Incredible Hulk), who then causes chaos to the school (eating 15 folding chairs and the gym teacher in the process). Captain Underpants then appears thanks to the kids calling for him. He then rapidly shoots underwear at the monster, but it doesn't work since the monster keeps eating them. So the Captain ends up running around everywhere with the Hunk chasing him until eventually the Hunk becomes too tired and thirsty to continue the chasing, so Captain Underpants tricks him into going into the bathroom so he can get a drink of water there. The monster is fooled by this and drinks out of one of the toilets. Captain Underpants then flushes the Inedible Hunk down to the sewers. Captain Underpants then flies off with the principal and the kids waving goodbye as the comic ends.
On the back of the comic, there is a notice reading, "Don't miss our next adventure: Captain Underpants and the Attack of the Talking Toilets, Coming soon to a playground near you."