The outside of the animal shelter has a design made of rusting metal. It also has barbed wire at the very top and the place's name written in the middle in black text. The roof and door of the building are gray.
The inside of the animal shelter resembles almost the inside of a prison. It has many cages that keep non-anthropomorphic animals locked away.
This is where Plankton goes to find his new pet, Spot.
Spot eventually runs away from Plankton and back to the animal shelter. Plankton goes with SpongeBob to retrieve Spot from here. After a lot of threatening animals are accidentally freed from their cages due to SpongeBob turning on the wrong switches, Spot shapeshifts into a large height to deter them away.
"Gary & Spot"
When Marvin captures most of the animals at the dance party, Gary and Spot (the only ones to evade Marvin) decide to follow him to the animal shelter and free their friends. While there, they overhear Marvin bemoaning his lonely life, causing the animals to try and help him by setting him up on a date with a girlfriend Gary made from slime.
After several dates, Marvin and his girlfriend, now named Alice, get married inside the animal shelter. Marvin expresses his gratitude to Gary, Spot and their friends for helping him, and releases them all from the animal shelter.