Drake wants to expose Big Yellow as a monster for eating his friend Willie.
A year has passed since Willie disappeared, at least, that's what most of Yellow Valley High School thinks. Willie's friend, Drake, knew that the school's mascot, Big Yellow, ate Willie alive, as did Wolfie, the latter who was supposed to be the succeeding mascot after Big Yellow. It was all up to Drake to expose Big Yellow as a monster, and not a normal mascot. (Opening Credits)
But Coach Butchko wouldn't give any comments about how Big Yellow came to be, even if Drake tried. Drake kept on searching for answers, that is, until one day, in the locker room, he found a diary under one of the lockers, and found some proof; Coach Butchko was hiding something... (Commercial break)
In the early eighties, Yellow Valley High School was looking for a mascot for their sports teams. Three friends, Billy, Calem and Sally, were to judge on who would be the mascot. Their choices ranged down to a hornet, a duck, and a weird hairy creature, all yellow to match the name of their school. Since other mascots wound up missing (or so Billy, Calem and Sally thought), they rounded the choices down to those three. (Commercial Break)
One night, before the homecoming game, both the hornet and the duck mascots mysteriously dissappeared. At the game, it was announced that, even though the hairy mascot got the lowest score, and the hornet and duck mascots were nowhere to be found, the hairy mascot won by default and will be known by that night forward as "Big Yellow". But something weird was going on, and the three friends decided to investigate.
Looking for clues, Calem and Sally have found remains of the hornet and duck costumes, that is, before they mysteriously disappeared. Now all that remains is Billy. Before he could go any further, he found a note written by Big Yellow, saying that he will never see Calem or Sally again. Big Yellow has devoured them, and if he was to reveal that Big Yellow is really a monster, he'll get eaten, too.
It was later revealed that Billy grew up to become Yellow Valley High's coach, keeping Big Yellow's identity a secret. Drake had figured out that if he'd try to reveal Big Yellow as a monster, he'll get eaten, too. So, he must figure out a way to expose Big Yellow for the monster he really is, and tonight is the homecoming game. (Commercial break)
At the homecoming game, Drake and Billy are getting ready to expose Big Yellow. After that, Big Yellow is insulted by a teenage biker, so Big Yellow in revenge eats him alive making the biker scream. Drake and Billy hear this and see it is on video. But Billy gets eaten by Big Yellow but Drake knocks the monster out and cuts it open with a knife, killing Big Yellow. Now that Billy is free, him and Drake free other victims.
The next morning, Big Yellow is finally exposed as a monster and burned alive by the students and teachers. Drake is happy that Willie and Wolfie are alive. Drake is honored a hero by the school. (End credits) (I don't wanna go to school song plays during the credits).
Epilogue: R.L. Stine sucks Big Yellow inside the episode's manuscript.