It closely resembles Squidward. It is a light turquoise gland with lavender veins and light yellow eyes with mahogany-brown pupils.
Role in episode
When SpongeBob and Patrick are in Squidward's bedroom to watch the sunrise with him, they are too loud and wake up Squidward. He asks them if they remember what happens to his brain every time he sees them, and SpongeBob gladly tells a story about Squidward's happy gland.
It is inside Squidward's brain. Everytime Squidward sees SpongeBob and/or Patrick, dark storm clouds form inside Squidward's brain. When the storm comes, the happy gland tries to use its umbrella to shield itself from the storm, but the umbrella flies away which causes it to get the flu. This means it is not able to keep Squidward happy.