Hallelujah: Leonard Cohen, a Journey, a Song (2021)

Due to a faulty door, the Sealab crew gets locked in a tool closet. A few black eyes result as they try to get out, but then they discover that a pack of unfed killer dogs are running around Sealab.

Sparks starts pushing a new, "mostly kelp" energy pill that proves to be highly addictive.

Behind the scenes at the chaotic "set" of Sealab 2021. In this episode, the voice actors use their own names rather than the characters'. The episode is a parody of Living in Oblivion by Tom DiCillo.

A series of unexplained thefts leads Murphy to declare "Martian law". In the ensuing madness, everyone ends up blaming Quinn for all the thefts.

After running up thousands of dollars in credit card debt, Murphy can't come up with a way to pay for it all...until Sparks intervenes. He takes out life insurance policies on the crew before sending them on a fatal fool's errand, and proceeds to kill Captain Murphy with a homemade tesla coil in the hot tub. However, Captain Murphy grabs Sparks as he is being electrocuted, killing Sparks as well.

A mysterious Asian visitor brings an irresistibly cute Gloop (reminiscent of shmoos) onto the station, which Murphy names Squishface. There are two problems, though: Gloops stink, and they multiply so fast that eventually Sealab is overrun with them. This episode parodies "The Trouble With Tribbles", Gremlins, and Aliens. There is also a reference to the popular fps shooter Return to Castle Wolfenstien when Debbie calls out "I need ammo!" and a bullet icon appears over her head.

Who should come aboard SeaLab but the Bizarro versions of the crew, such as Bizarro Debbie, Bizarro Marco, Bizarro Murphy, Bizarro Sparks, Bizarro Stormy, and a sort-of Bizarro Dr. Quinn. The Bizarros hold the real crew captive, before beginning to torture the real crew. With Bizarro Torture.

Murphy's golf game is, due to a lack of golfballs, cut short. Murphy embarks on a frantic quest to find the Pro Shop. On the way, Murphy runs into a Monster-Hesh, snotty telephone operators, the Dolphin Boy, and a perfidious Eggers.

The crew of Sealab (along with a vapid gossip-show host, a bear in lederhosen and guest stars Kid 'n Play) star in a sneak preview special for the movie Tinfins, complete with plenty of ads for the restaurant Grizzlebee's: "You'll wish you had less fun".

A nuclear submarine crashes outside the station, and the crew of Sealab (in a rare occurrence) must work quickly to stop an environmental disaster from happening.

Capt. Murphy's attempts at a happy Alvistide go awry thanks to non-Alvian crew members, an uncooperative electrician, and Alvis himself "crapping the buffet".