In "Chocolate with Nuts," it is a fat rectangle shape (almost a square) and it is deep purple with thin goldish-yellow sides. It has a red diagonal line going from the bottom left corner to the top right corner.
In "Life of Crime," it is still a rectangle, but skinnier and longer. It is also brown and reads "CANDY" in pink and all capital letters. In "Safe Deposit Krabs," it is once again a rectangle, but this time, it is half-eaten, has blue wrapping paper, and pink text that reads "CHOCOLATE."
For the entire episode, SpongeBob and Patrick decide to sell chocolate bars in order to start living the fancy life. In the beginning, they don't do so well, as they are constantly being chased by a crazed Tom yelling "Chocolate!" and being conned by a fish, though SpongeBob and Patrick didn't know that they were being conned the entire time. SpongeBob finally gets an idea to sell chocolate by "stretching the truth."
This works out to much success, as they managed to sell many bars of chocolate to most of the people of Bikini Bottom. However, they end up being conned by the Con Man after he fakes being in a full body cast. When SpongeBob and Patrick look like they are going to give up, Tom appears again and scares them. However, he ends up buying all of SpongeBob and Patrick's chocolate with a huge stack of money and the duo can finally start living the fancy life. They end up buying a fancy restaurant and go on a date with two much older fish.
Chocolate bars make a small appearance in this episode but play a major role for the climax. After Patrick thinks they are going to starve, SpongeBob takes out two chocolate bars for them to eat. Patrick ends up eating his chocolate bar but then doesn't know what happened to it. He then accuses SpongeBob of taking his chocolate bar and wants him to give it back.
SpongeBob denies trying to tell Patrick that he already ate it but Patrick doesn't budge. SpongeBob even offers to share his chocolate bar but Patrick still thinks he stole his and wants him to admit he took it. SpongeBob gets fed up with Patrick and finally decides to eat his chocolate bar. He eats it very slowly as a means to torture Patrick and finally finishes the bar. Patrick, furious, then decides to tell on SpongeBob for stealing the balloon earlier in the day, to which SpongeBob reacts to tell on Patrick for doing the same.
They both head into a police station and tell the two policemen what happened. SpongeBob and Patrick only go into jail for a few seconds after the policemen tell them they stole the balloon on National Free Balloon Day.
Also, in "Chocolate with Nuts," Patrick calls them "chocolate bars," but in this episode, he calls them "rectangles," likely because of their shape and his stupidity.
After Patrick suggests that he and SpongeBob take out a dollar bill from his wallet to replace Mr. Krabs' First Dollar which they got paint on, SpongeBob agrees with this idea and encourages him to do so, however, Patrick, being his dumb self, decides to waste it on a chocolate bar from Mr. Krabs' vending machine. Afterwards, Patrick eats some of it and asks SpongeBob if he would like a bite.
When Squidward commands SpongeBob to do a task so simple that even someone without a brain could do it, the latter informs the former that he gave his brain to Patrick in exchange of two chocolate bars. He is later seen eating them when he is stuck inside Squidward's vacuum cleaner and his brain has been given back to him in the process.