The Electric Clarinet is a clarinet that only appears in the episode "Sold!"
The Electric Clarinet consists of Squidward's original clarinet with a faded green speaker attached to the end. Squidward puts a very loud speaker into the clarinet to make it louder than a regular clarinet.
Role in episode
When Squidward pretends a musical band lives under Patrick's rock, Squidward says the Electric Clarinet is one part of his band. Patrick says that there's no such thing, so Squidward hastily makes one and shows it to Patrick.