If you were looking for the article about the parody version, then see Pop Kelp.
Popcorn is a snack food item that is served at Reef Cinema and by some food vendors at special events. It first appears in the episode "F.U.N."
It is a puffed-up variety of corn kettle that is typically light yellow. It is a common snack served at movie theaters, in the series' case, Reef Cinema.
Role in series
SpongeBob throws a piece of popcorn in Bubble Bass' direction in an attempt to get to stop sitting on Plankton.
Pearl's friends are served popcorn at her birthday party, which they deem to taste stale.
SpongeBob cooks a pan of corn kernel above his stove, which results in his living room filling to the brim with popcorn.
The food vendor sells popcorn and peanuts at the Krusty Krab Stadium.
SpongeBob and Patrick eat a bowl of popcorn while watching a real estate commercial on TV.
SpongeBob and Patrick eat popcorn out of Gary's bowl.
SpongeBob offers a starving clown a piece of popcorn but is swiftly prevented by the ringmaster.
SpongeBob adds a popcorn machine to his living room to fancy up the atmosphere, enthusiastic about seeing the lost episode of Mermaid Man and Barnacle Boy.
As a result of SpongeBob accidentally leaving the VCR recorder on, destruction occurs inside SpongeBob's house and thus spills the popcorn all over his living room.