The golden clarinet is like Squidward's original clarinet but painted gold by Plankton when Squidward wasn't looking. It sounds "beautiful," according to Squidward.
Role in episode
SpongeBob asks Squidward to make a wish as SpongeBob wants three wishes granted for three of his friends, including Squidward. SpongeBob, not realizing that the genie was Plankton inside the Genie Bottle, takes him to Squidward, and knocks on his door. Squidward, not believing SpongeBob, wishes for "a golden clarinet that sounds beautifully." Plankton disappears and quickly goes into Squidward's house and paints his original clarinet golden with paint when Squidward isn't looking. Plankton later throws the bucket of golden paint and the paintbrush into the garbage can, and hides inside the clarinet. Squidward notices the clarinet and is surprised. He then plays the clarinet, and with the sound being perfect in his standards, he is in amusement. Later in the episode Squidward tries to possess that bottle, along with Patrick and Mr. Krabs who were also surprised by the bottle.