Sealab 2021 - Season 4 (2004)

When Shanks refuses treatment for a festering, pulsing head-tumor, the crew decides to dust off the old shrink ray and then basically reenact the plot of a 1960's sci-fi movie starring that actress.

Sealab secedes! (From whom, and lots of other pertinent issues, to be discussed more fully during the actual episode.)

Enter the sinister and mysterious world of the Neptunati, a secret organization that holds the fate of the world in its clutches. And which also, for some reason, has Shanks as a member.

A team-building exercise goes horribly wrong when the Sealab crew are attacked by Chupacabras on an island named Happy Funtime Island.

The death of Marco has hit the crew of Sealab hard, so a grief counselor is at hand to help.

There's a zombie invasion at Sealab as Debbie plans her (fifth) 30th birthday party.

With Marco's untimely passing, his illegitimate son applies for a job on Sealab. In order to get hired or at least get qualified, he must pass the civil service exam.

Marco returns from the dead. What really happened with him?