Sandy's treedome is Sandy Cheeks' place of residence. It is notable for being the only place in the entire Pacific Ocean in which Sandy can live (because Sandy breathes air). It first appears in the episode "Tea at the Treedome."
Its most notable feature is the powerful, nearly-impenetrable airtight 35-foot tall polyurethane dome that surrounds it, letting no water seep in, allowing Sandy to survive without her special pressurized suit. On the inside of the dome, there is a picnic table, hamster wheel, and a bird bath.
Despite this home being on the same street (and one home next to SpongeBob's, similar to Squidward's home), it is never seen directly next to the Pineapple home, or even anywhere near a street, for that matter. Inside the dome, there is grass and sometimes flowers. There is a large oak tree in the center that provides Sandy with oxygen and acorns. The tree also serves as Sandy's house.
The treedome also has a mechanism that covers the dome with a layer of riveted sheet metal when Sandy wants her privacy. Other notable features are a boxing ring, weight lifting equipment and the "Arm Cruncher"—as seen in "MuscleBob BuffPants," an exercise hamster wheel, clothesline for hanging Sandy's suit and clothing to dry - as seen in "Prehibernation Week," a garage for Sandy's jeep-like boatmobile—as seen in "To Save a Squirrel," an escape pod to Texas, a picnic bench, and Table, a miniature submarine for emergencies—as seen in "Hide and Then What Happens?," and a rocket to the Moon - as seen in "Sandy's Rocket."
In the winter, there is snow which covers the whole ground and sometimes there are no leaves on the tree. It is also very cold. This is seen in the episodes "Bubble Buddy" and "Survival of the Idiots."
Inside the tree
Inside the oak tree, there is a bedroom with a wooden bed, a rocking chair and nightstands (and possibly a closet and drawers) made out of sticks from the tree. In "A Flea in Her Dome," it is shown that there is an automated trapdoor in her room which is stationed over a metal slide that leads outside the tree. It is unknown how all this stuff can fit inside a tree. There is a large living room with rugs, a television, and wicker sofas and chairs. While not shown, Stephen Hillenburg says that, like SpongeBob's pineapple, the treedome has a massive library, probably filled with books on science, the ocean, technology, etc. There is a bathroom with a shower stall. It also has a tree stump for Sandy's spacesuit, and a hook to hang her fur pelt when she's not wearing it. There is also a sink and medicine cabinet. Strangely, its lock is on the outside. Some of this can be seen in the episodes "Someone's in the Kitchen with Sandy," "Survival of the Idiots," "Pranks a Lot," "A Flea in Her Dome," and "MuscleBob BuffPants."
The treedome has seen many visitors and inhabitants. Only some of them are below, which are separated into two groups; land creatures and sea creatures. Due to there being no water and only air in the treedome, land creatures can live in there, while sea creatures must wear large helmets with water in them on their heads so they don't dry out or get dehydrated. This is a parody of Sandy's required air dome when out in the ocean. Occasionally the domes are designed like fishbowls, other times they're sealed. Sandy Cheeks: The primary resident of the treedome. She uses it as a home to survive underwater with. She also uses it to create inventions for her chimp bosses. She also practices karate with SpongeBob here, takes care of her pets, and more. Wormy and Sandy's other pets: In the episode Wormy, Sandy has many fellow land animals as pets to keep her company, with the most notable being Wormy.
In his premiere episode, "Wormy," Sandy left on a trip and made SpongeBob and Patrick take care of her pets. SpongeBob, Patrick, and Wormy immediately became best friends, and they left to go to sleep, promising to play the next day. However, SpongeBob and Patrick didn't know almost anything about land creatures and didn't know that Wormy was, in fact, a Monarch caterpillar, and overnight, he went through metamorphosis (which would actually take several weeks) and became a Monarch Butterfly.
When SpongeBob and Patrick came the next day, they thought it was a monster that had eaten Wormy, became terrified, accidentally let it loose into Bikini Bottom (it got trapped in one of SpongeBob's bubbles, giving it air to survive in), and SpongeBob and Patrick "warned" the city, resulting in mass hysteria, which stopped when Sandy came back and "trapped" Wormy in a jar, much to the relief of the Bikini Bottomites. Professor Percy: One of Sandy's chimp bosses. Like his fellow chimps, he premiered in the episode, Chimps Ahoy; when he came to inspect Sandy's inventions to judge if she could stay longer. Like the other chimps, he has a British accent.
Due to Sandy running away since she thought she wasn't any good, so SpongeBob and Patrick invented a combo-back-scratcher/ukelele-tuner/nose-picker to impress him and the other chimps. This failed miserably after Lord Reginald was severely wounded by the machine. However, Sandy's Treedome was saved when Sandy automated-nutcracker (which wouldn't even try) was shown to excel at peeling bananas. In gratitude, they gave Sandy a pay raise and a 20-year contract. Professor Percy mentioned that he hopes she can invent an automated poop-throwing machine. Dr. Marmalade: One of Sandy's chimp bosses. Like his fellow chimps, he premiered in the episode, Chimps Ahoy, to inspect Sandy's inventions to judge if she should stay longer. Lord Reginald: One of Sandy's chimp bosses. Like his fellow chimps, he premiered in the episode "Chimps Ahoy"; when he came to inspect Sandy's inventions to judge if she could stay longer. Like the other chimps, he had a British accent.
SpongeBob SquarePants: A good friend of Sandy and Patrick. Likes to come to play with Sandy, practice karate with her, or sometimes even help Sandy with her inventions. He usually
causes much less chaos than Patrick in comparison. Patrick Star: A good friend of both SpongeBob and Sandy. He usually comes with SpongeBob to play with Sandy. He usually causes havoc to the treedome and Sandy's inventions. Squidward Tentacles: A partial friend of Sandy, who doesn't spend a lot of time with her. He got help from Sandy, SpongeBob, and Patrick in the episode "Squidtastic Voyage"; to get the reed of his clarinet removed from his throat. Eugene H. Krabs: He once went in in the episode "Overbooked", since SpongeBob was there, and he needed his help with a telescope. Sheldon J. Plankton: In the episode "Someone's in the Kitchen with Sandy," he accidentally was brought in with Sandy's suit. He stole Sandy's fur pelt and helmet while she was in the shower.
All of the other inhabitants of Bikini Bottom: At the end of the episode, "A Flea in Her Dome," they were sucked into the treedome when Sandy opened the treedome to flood it with water to drown the invading fleas inside.
"Dying for Pie" - Probably got destroyed after an incident of a pie explosion.
"The Krusty Plate" - Same as "Dying for Pie," it probably got destroyed after an incident of a maximum power.
"Hide and Then What Happens?" - SpongeBob flew out in a submarine causing it to make a hole and fill up.