Undyne's Letter

Undyne's Letter is a letter that Undyne gives to the protagonist to deliver to Alphys in the True Pacifist Route. After the protagonist delivers the letter, Alphys engages in a date with them.
Undyne gives the protagonist Undyne Letter EX as a replacement if the original letter is thrown away. Undyne Letter EX cannot be thrown away or sold at the Tem Shop.
== Flavor Text ==
* [Use]
** You tried to open the letter, but...
** It's been shut so tightly, you'd need a chainsaw in order to open it.
* [Undyne] OH MY GOD!!! I'M GONNA FREAKIN' KILL YOU!! [Use in Snowdin Town]
* (Maybe if you check the lab door, you can slide it underneath...) [Use in Laboratory Entrance]
* (Despite what seems like common sense, you threw away the letter.) [Drop Undyne's Letter]
* [Undyne] Hey! Don't throw that away! Just deliver it! [Drop Undyne's Letter in Snowdin Town]
* [Examine Papyrus's mailbox with letter in inventory]
** [Undyne] Oh my god! The letter's not to PAPYRUS!!!
** [Papyrus] YEAH, UNDYNE'S GOT A POINT!
** [Papyrus] WHY DIDN'T SHE WRITE A LETTER TO ME INSTEAD?
** [Undyne] Fine, you want a letter!?
** [Undyne] I'll give you a letter!!!
** [Undyne] YOU GET AN "F"!
** [Papyrus] OH NO!!!
** [Papyrus] WHAT'S THE F FOR?
** [Undyne] Friendship!!!
* (The letter is too powerful to throw away.) (It gets the better of you.) [Attempting to drop Undyne Letter EX]
== Main Story ==
If the protagonist spares Flowey after his battle in a pacifistic Neutral Route (that is, no EXP earned) and has already befriended both Undyne and Papyrus, he tells the protagonist to backtrack and see Alphys. After reaching the bridge that connects the CORE and MTT Resort, whether or not Flowey was spared, Undyne calls the protagonist and tells them to come to Snowdin. In Snowdin, Undyne gives the letter to the protagonist.
If the protagonist spares Flowey and has not befriended Undyne or Papyrus, Flowey instructs the protagonist to befriend the two characters. In this case, Undyne gives the protagonist the letter after they hang out. Befriending Undyne is only possible if the protagonist has gained no EXP.
When delivered to Alphys, she debates whether or not to read it before chastising herself, and opens it with some loud machine (possibly a chainsaw). At first, she believed the contents to be a joke being played on her and decides to confront the person who delivered it.
Alphys becomes flustered when she realizes that the protagonist is on the other side of the door; she believes that they wrote the letter since it was unsigned. She then goes on a date with the protagonist.
Undyne's letter cannot be sold in the Tem Shop. Its price is replaced with "NO!G." Attempting to sell it regardless causes one of Mettaton's soundbytes to play.
== Trivia ==
* The Use flavor text references the chainsaw that can be found on the second floor of the Lab, atop Alphys's work table.
** The sound effect played just before Alphys opens the Lab's doors after receiving the letter is internally named "mus_sfx_chainsaw.ogg", indicating she did use a chainsaw to open the letter.
** Mettaton also uses a chainsaw in the "Cooking with a Killer Robot" show segment.
* If the protagonist's last SAVE before fighting Flowey is prior to CORE, there are several alternative triggers for Undyne's phone call.
* If Flowey was previously spared on a Neutral Route that did gain EXP, he advises the protagonist to complete another run without killing anything. Following this instruction results in similar advice to befriend Papyrus, Undyne, and Alphys.
== References ==
de:Undynes Brief
es:Undyne's Letter
fr:Lettre d'Undyne
ja:Undyne's Letter
pl:Undyne's Letter
ru:Письмо Андайн
zh:Undyne的信