Lab

The Laboratory is the workplace and home of the Royal Scientist, Alphys, in Hotland. It is a single building where Alphys conducts her studies, controls sections of Hotland's puzzles, and surveys the majority of the Underground through hidden cameras. It also houses the True Lab.
== Features ==
* A package of Instant Noodles can be obtained from Alphys's fridge.
* Alphys and Mettaton make their first appearances here, with the latter subjecting the protagonist to a quiz show.
* The True Lab, initially disguised as a bathroom, is found here, containing the results of Alphys's ill-fated experimentation with SOULs and Determination.
== Main Story ==
=== Neutral Route ===
After escaping Undyne in the Neutral Route, the protagonist enters the Lab with the lights off. Aside from the monitor, they cannot inspect anything as it is too dark. Alphys turns on the light and introduces herself and her intent to guide the protagonist after watching them, though she warns them of Mettaton, a robot she created. Shortly after, Mettaton breaks through the wall and subjects the protagonist to a quiz show. Afterwards, Alphys notices the protagonist's dated Cell Phone and upgrades it. She immediately excuses herself to go to the "bathroom," making it inaccessible. Once the protagonist exits the Lab, Alphys realizes that she did not watch the encounter between Undyne and the protagonist. After they defeat Mettaton EX, the doors to the Lab are locked, making most of floor 1 of Hotland inaccessible.
In the Alphys Ending of the Neutral Route, achieved if the protagonist aborts the Genocide Route before reaching Mettaton NEO, it is implied that when Alphys evacuated the monsters, she brought them to the True Lab. Alphys tells them that she knew she had to do something about the protagonist's actions, even if it meant that the monsters would learn the truth about her.
=== True Pacifist Route ===
In the True Pacifist Route, the protagonist goes to the Lab to deliver a letter from Undyne to Alphys. Alphys reluctantly opens it and mistakes the protagonist as the writer of the letter. She then goes on a "date" with them in the Garbage Dump, with Undyne and Papyrus making appearances. After the training, Papyrus sends her back to the Lab and calls the protagonist to recommend they go there as well.
The protagonist can explore the Lab to find new objects. Checking the garbage can between the computer and monitor reveals that someone sent an intimidating message to Alphys, simply saying "I KNOW WHAT YOU DID," written in a strange handwriting. The "bathroom" is open, and near the doorway is a note from Alphys addressed to her friends, telling them that she needs to face her mistakes and that "the truth" is past the door. On the second floor, Mettaton's deactivated body can be found on Alphys's working table.
When the protagonist enters the door, it is revealed to be an elevator that descends into the True Lab.
=== Genocide Route ===
In the Genocide Route, Alphys watches the battle between the protagonist and Undyne. The lights in the Lab are already on, and Alphys is not present. Instead, Mettaton appears and explains that Alphys has been evacuating everyone to a safe location. Mettaton leaves after the protagonist approaches him aggressively.
== Geography ==
The Lab is a large white and red building with a pale green interior. There are two floors on the lab, the ground floor being Alphys's workplace, and the second floor being her room. Three conveyor belts are also in the Lab, with two leading to the other floor, and one on second floor that moves to the left.
On the ground floor, there is a console with a monitor where Alphys monitors the protagonist, a "cute" garbage can, a messy computer desk with papers and bowls, a fridge filled with Instant Noodles and soda, a bag of dog food, and the elevator, which has a bathroom sign beside the door. After Mettaton's appearance, there is a hole in the wall between the elevator and the dog food.
In the True Pacifist Route, the garbage can has a crumpled paper with the words, "I KNOW WHAT YOU DID." On Alphys's computer desk, there are papers that are implied to be for a game walkthrough written in "chicken scratch," the computer itself, which has access to Snowdin Forest's Multicolor Tile Puzzle, a yellow lizard teacup filled with soda, and figurine of a "female human with cat ears." Inspecting the hole notes that the space is only a few feet wide. In the Genocide Route, it is described as being there to "complete the look."
On the second floor, there are five shelves, four labelled as "Human History:"
* Light green: Dusty scientific books.
* Green: Books, with one being a comic of a "giant robot fighting a beautiful alien princess."
* Yellow: VHSes and DVDs of cartoons.
* Blue: Books, with one being a comic of "two scantily clad chefs flinging energy pancakes at each other." 
* Red: Books, with one being a comic of "a hideous android" running late to school.
Next to the shelves is an implied ice cream machine, hanging tools, a large, dusty work table with a chainsaw and a paper depicting SOULs, a poster of a character resembling Mad Mew Mew above it, a closet, a shelf with unopened letters from monsters and a lamp with pink fish, a compacted bed with a pink heart poster above it, and a poster of Mettaton's TV premiere, signed with a thank you.
On the True Pacifist Route, Mettaton's deactivated body can be found on the second floor for repairs.
== Trivia ==
* If the protagonist calls Papyrus outside of the Lab entrance, Sans alludes that there may be dogs inside the building.
** Calling Papyrus again causes him to have an additional related comment.
* In the Windows version of Undertale, the monitor follows the protagonist's movements, whereas the screen displays a static image in the macOS and Linux versions.
* Inspecting the console on different occasions yields different flavor text:
** When the lights are off, the dialogue becomes "It's you...?"
** When the lights are on, the dialogue explains the monitor's use. 
** In the Genocide Route, the dialogue is, "It's me, <Name>."
* The bag of dog food is described differently based on if the protagonist has killed any monsters:
** It is described as "half-full" if no monsters have been killed.
** If any monster is killed, the message changes to "half-empty bag of dog food."
*** A follow up message, "(You just remembered something funny.)" appears if Doggo, Lesser Dog, and Greater Dog are killed and the protagonist has 21+ kills.
* If Papyrus is called a second time on the first floor, he recalls seeing the dog food bag in Sans's room and asking Sans about it.
* The teacup that resembles Alphys is from Asgore.
* The Lab also features a neon "GAME SHOW" sign and disco ball lights during Mettaton's Quiz Show segment. While these are not acknowledged in-game, it alludes to the staged collaboration between Alphys and Mettaton.
* It is implied that the poster and the female human with cat ears figurine is of Mew Mew, a character from Alphys's favorite human TV anime, "Mew Mew Kissy Cutie 1."
** The poster and the heart poster shares the same design characteristics as Tokyo Mew Mew (also known as Mew Mew Power in North America), a typical magical girl romance anime.
* The comic involving a "giant robot fighting a beautiful alien princess" is referenced by Undyne on different occasions:
** During her monologue atop the craig.
** During the date with Undyne, she can admit to reading the comic book.
** After the date with Alphys, when Undyne questions if anime is real.
** In the True Pacifist Route epilogue, Undyne asks Alphys if they can watch something "with fighting."
* It is implied from Undyne's phone calls that Alphys converts the sea-grass from Waterfall to "chilly pink stuff" with the machine on the second floor.
** During Alphys's date, Alphys admits this to Undyne, and that the seaweed is not "scientifically important."
* The dress in Alphys's closet was picked out with the help of one of Alphys's friends.
* The dialogue for the garbage can and the single dress in Alphys's closet alludes to the date with Alphys.
* Some of Alphys's UnderNet statuses is of her taking pictures in the Lab:
** Alphys posts a picture of the garbage can, and claims that it was her at the moment.
** She takes a picture of a bowl of Instant Noodles with a "catgirl figurine."
* In the Nintendo Switch version of Undertale, it is implied through Mad Mew Mew's dialogue that her body was originally found in the Lab.
* It is possible to skip the entire scene with Alphys and Mettaton by interacting with the bag of dog food right when the scene begins. This has been dubbed the "Lab Skip."
** In v1.001, the hitbox of the bag of dog food was shrunk to prevent this from happening. However, because Toby Fox could not figure out how to replicate it, this did not fix it.
** The "Lab Skip" has been abandoned by the speedrunning community for the "Punch Card Exploit" since it is a much easier alternative to pull off.
* The bathroom sign and the switch around the entrance to the True Lab have been moved in Undertale v1.001.
* A rather amusing glitch before v1.001 can be pulled off by calling Papyrus and Undyne while on a conveyor. This causes the text and portrait to trail off the screen.
== References ==
de:Labor
es:Laboratorio
fi:Oikea Labra
fr:‎Lab
ja:‎Lab
pl:‎Laboratorium
pt-br:Laboratório
ru:Лаборатория
uk:Лабораторія (Справжня)
zh:實驗室