It is a white and blue soda drinking hat with a "number one" design in red. It has two holders for soda cans on both sides of the hat, with the tube of it being green.
Role in series
"One Krabs Trash"
The hat is sold by Mr. Krabs at his antique sale. Mainly SpongeBob wants it, so Mr. Krabs sells it to him, and he later converts it into a bubble blowing hat. Then, someone comes up and tells Krabs that he knows that he is selling that rare novelty drink hat. Mr. Krabs tells him it's fresh out instead of out of stock.
The man then prepares to give him five hundred dollars for the hat. After Mr. Krabs hears this, he starts slobbering out of his mouth. A woman then comes up and elbows the man and says that she would give him a thousand dollars for such a hat. Mr. Krabs slobbers some more when he hears that. Nat Peterson comes up and says that he would give him a hundred thousand dollars in cash for that rare soda hat. Krabs is now slobbering a river of drool out of his mouth. Fred comes in a boat, sailing through his saliva, and says that he'll give him one million dollars for the hat. After much regret, he is determined to take the rare hat back.
First, he attempts to insult the hat out of SpongeBob. His next step is to get SpongeBob to trade his hat for others. Since these plans end up failing easily due to SpongeBob's refusal, Krabs has no choice but to scare it off. In the middle of the night, he uses a picture of a ghost on loose leaf to send the message that the hat was cursed and has to be placed back to its rightful owner, Smitty Werben Man Jensen. Mr. Krabs realizes his plan has backfired when SpongeBob technically does return the hat to its rightful owner, and it turns out that there really is a deceased person named Smitty Werben Man Jensen and that the hat DID once belong to him.
He goes to the cemetery and searches every grave, then he finds the grave and the hat. Suddenly, the entire graveyard of dead fish come alive and demand the hat back. Mr. Krabs, not wanting to give back the hat, fights every last undead fish until dawn. The customers of his antique sale from earlier are all there, so Krabs could sell the hat for an astounding price. They then refuse and revealed that a warehouse full of those hats was found and that they are actually abundant and worthless. Krabs throws away the hat and cries as his chance for fortune is gone.
SpongeBob's Truth or Square
It is one of SpongeBob's memories.
It can be seen on the floor of SpongeBob's house, scattered around with numerous other objects when SpongeBob is bored.
"Lost and Found"
Three soda drinking hats are seen stacked one on top of another in the "Lost Novelties" section of the Lost and Found.