The Chumporium was a temporary replacement for the Chum Bucket, that appears in the episode "New Leaf". It only sold items and trinkets.
The Chumporium looks exactly like the Chum Bucket, except that it has been turned into a gift shop. It has a large yellow poster covering the word "Chum Bucket" on the outside that reads, "Chumporium" in green capital letters. Underneath, in blue, it says "Grand Opening."
The glass doors lead into the inside of the Chumporium.
The owner is Plankton, who had been running the Chum Bucket for years. Its only known customer is SpongeBob (when he bought a Snow globe). Suspicious, Mr. Krabs confiscated SpongeBob's snow globe and threw it into his storage with Plankton's other past ideas used to get to the Krabby Patty formula.
Mr. Krabs, after throwing a party, noticed Plankton walking out of the Chumporium with a seal plush-doll, and noticed something. He looked through a window and was shocked at what he saw inside. Not convinced, he gave Plankton "A War." It may not have been a success, but Plankton had loved his gift shop and was heartbroken when Mr. Krabs went on a rampage. It included lava lamps, trinkets, stuffed animals, and all other kinds of things.
Plankton tried to act as if he was not trying to capture the Krabby Patty secret formula but Mr. Krabs proved smarter. Plankton later tore down the sign and brought back the Chum Bucket. This transformation was only seen in the episode "New Leaf."