Mopatop's shop has an assistant named Puppyduck, who is a hybrid duck/dog-like creature as her name would suggest. There was also a mouse character named Moosey Mouse who lived in the ceiling of the shop with his parents, and generally went unnoticed by Mopatop and Puppyduck when he was visiting the shop. The show depicted Mopatop and Puppyduck's interactions with customers, who generally wanted to buy stuff that no one would expect to find in a real store (e.g. an opera singer wanting to buy a partner to sing with, a fisher who wants a river to use his fishing equipment in, etc.).
- Bottle Episode: Episodes generally take place within the shop and don't move anywhere else.
- Cartoon Creature: Mopatop vaguely resembles a dragon, but other than that it's never really explained what species he is. Puppyduck, on the other hand, might be an exception to this trope, if her name fitting her duck/dog hybrid appearance is anything to go by.
- Character in the Logo: Mopatop appears in the logo, holding the title of the show in his hand.
- "Double, Double" Title: The episode "Rumble Rumble".
- Every Episode Ending: The big clock in the shop goes off at the end of every episode, prompting Mopatop and Puppyduck to close the shop.
- Growling Gut: Puppyduck's stomach growls a few times in the episode "Rumble Rumble".
- Hates Baths: One episode featured a customer who wanted some dirt to roll in. His mother had asked him to get a bathtub, but he hates taking baths... that is, until he is eventually convinced that Baths Are Fun and decides to get a bathtub anyway.
- Invisibility Ink: One episode featured an invisibility machine that sprays an unidentified substance onto whatever object to make it invisible. The machine is itself invisible, and so is the substance it sprays.
- Mix-and-Match Critters: Puppyduck resembles a mix between a dog and a duck.
- Muppet: With this being a Jim Henson show and all, every character is this.
- The Place: The show's title refers to the store in which all of the episodes take place.
- Punny Name: Mopatop's name is meant to sound like "mop it up", which makes sense since he does mop up stuff sometimes.
- We Sell Everything: The shop sells "anything that you could ever think or dream of", up to and including stuff that would be impossible to find in a real-life store (such as a puddle), non-physical items (such as hot and cold), and even fictional items (such as lettuce that hums).