The electric clarinet is a clarinet that 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, he says the electric clarinet is one part of his band. Patrick says that there is no such thing, so Squidward hastily makes one and shows it to Patrick.