SpongeBob and Patrick are racing to Sandy's Treedome to play. However, the dome has a metal cover on it, and a "KEEP OUT" sign on. They go inside the entrance, where they find a television. The television turns on and plays a video, which shows Sandy in a nightgown, eating acorns to store up for the winter. Sandy (on the TV) explains that she is hibernating for the winter. However, when they make too much noise in her room, she suddenly gets up, sleepwalking, and attempts to kill them, believing them to be "Dirty Dan" and "Pinhead Larry," outlaw villains from her dream. However, she soon falls back into her bed, asleep, with Patrick making sure she won't get up again by giving her a pair of earmuffs made from his bellybutton lint. SpongeBob and Patrick leave the tree to play in the snow. They pretend to be Dirty Dan and Pinhead Larry, mocking Sandy, and then begin fighting over which one of them is Dirty Dan. However, the vibrations from them whacking each other with a huge snow shovel (SpongeBob) and a massive baseball bat with a nail through it (Patrick) knock off the earmuffs, allowing Sandy to hear the ruckus, which alerts Sandy, who comes out of her tree and begins to attack SpongeBob and Patrick. She immediately throws Patrick aside when he is not looking, and then chases SpongeBob until he falls into a pit. SpongeBob tries to throw a small piece of wood at her, but Patrick comes and gets in the way, accidentally taking the hit. He falls into the ditch and then Sandy pounces on them, beats them up, buries them alive, and goes back to bed. As the winter storm grows more intense, SpongeBob and Patrick try to escape, but find that the door's frozen shut. Unable to survive in the cold weather, they go into Sandy's tree and rip off all her fur, SpongeBob makes his share into an "eyebrow/goatee combo" and Patrick fills his pants with the fur he ripped off. SpongeBob proclaims that he is prepared for the "longest, coldest Winter ever!!" However, Winter quickly comes to an end and Sandy wakes up, normal sized. She is surprised to see SpongeBob and Patrick, but soon realizes that they are wearing her fur and she is furless. The last scene shows Sandy drinking lemonade with SpongeBob and Patrick, whose bodies are wrapped around her to make her warm.
According to the Season 2 DVD commentary and in the storyboard, there's a deleted scene where Sandy's bed was hanging from the ceiling, and there was much more saliva/drool. Also stated in commentary, the original title was "Survival of the Morons."
This episode could be seen as a sequel to "Prehibernation Week." However, Sandy explained hibernation to SpongeBob in that episode, yet he still does not know what it is in this episode.
It previously snowed in the episode "Christmas Who?"; however, SpongeBob and Patrick act like they have never seen it until this episode, but it could be due to the episodes not being in order.
According to commentary, the original title was to be "Survival of the Morons."
In the original storyboard, Sandy's bed was hanging from the ceiling, and there was much more saliva, this was likely cut due to sexual mimicking.
Sandy's treedome was previously shown during the Winter in "Bubble Buddy." However, oddly, that time she had to go south to survive it, unlike in this episode.
The face that Patrick makes when he says, "Who you callin' Pinhead?" has been parodied countless times over the internet, and has become YouTube's popular meme.
At the end of the episode, when the snow has melted and Sandy first sees SpongeBob & Patrick with her fur, there is no water left in the treedome. However, this doesn't affect them. Similarly, earlier in the episode, when they were depending on snow for hydration, they are not affected by the lack of snow while inside Sandy's Tree.
In Bahasa Indonesia, the scene where Sandy is infuriated when SpongeBob & Patrick stole her fur, she grunts rather than mentioning their names (though in it's airing in Indonesia shows her yell their names out of anger along with grunts).
Also, the scene where Patrick and SpongeBob attacked by Sandy rarely shown in Indonesia due to time constraints as it was aired along with ads and violence.
The title is a reference to "Survival of the Fittest."
The scene when Sandy throws Patrick can be inspired to make the Tank animation from Left 4 Dead.
In the pilot episode of Fox's drama series Fringe, the beginning of this episode can be seen briefly.
When Patrick says "Look, she's on the eating channel," he is probably referencing Food Network or another channel involving food.
After Sandy grabbed SpongeBob and Patrick the 1st time and went back to bed, she was not wearing her blanket. The next time she was shown, she was wearing her blanket.
When Sandy rips off the top of Patrick's head, fangs are shown in her mouth. These are not seen any other time.
When SpongeBob & Patrick pop out from the snow they both have big straight noses made of snow, but when Patrick says, "That must be one tired tree!", Patrick's snow nose is bent down and SpongeBob's snow nose is bent upward.
When Sandy pounces on Patrick & SpongeBob, SpongeBob's feet are missing and Patrick has sharp teeth (right).
Sandy's lips don't move when she says "Oh look, it's SpongeBob and Patrick!"
When SpongeBob is standing next to Patrick, he has ice and snow on his head. When he runs to the tree it vanishes. When he returns to his spot, it's back on his head as if it never left.
When it becomes spring, SpongeBob & Patrick aren't wearing helmets & didn't dry up.
Even though there was no water or snow in Sandy's treedome, SpongeBob and Patrick went in without helmets unaffected.
When SpongeBob is in the hole and picks up a plank, there is another plank behind him. When the scene changed to Sandy and back to SpongeBob, the plank is gone.