- You tried to open the letter, but... | It's been shut so tightly, you'd need a chainsaw in order to open it. [Use]
- OH MY GOD!! I'M GONNA FREAKIN' KILL YOU!! [Use in Snowdin]
- 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]
- Hey! Don't throw that away! Just deliver it! [Drop Undyne's Letter in Snowdin]
- Oh my god! The letter's not to PAPYRUS!!! | YEAH, UNDYNE'S GOT A POINT! | WHY DIDN'T SHE WRITE A LETTER TO ME INSTEAD? | Fine, you want a letter!? | I'll give you a letter!!! | YOU GET AN "F"! | OH NO!!! | WHAT'S THE F FOR? | Friendship!!! [Examine Papyrus's mailbox with letter in inventory]
- The letter is too powerful to throw away. It gets the better of you. [Drop Undyne Letter EX]
If the protagonist spares Flowey after his battle in a Neutral Route, he tells the protagonist to backtrack and see Alphys. After reaching the bridge that connects the CORE and MTT Resort, Undyne calls the protagonist and tells them to come to Snowdin. In Snowdin, Undyne gives the letter to the protagonist.
If the protagonist defeats 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 opening 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 the protagonist wrote the letter. 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," and if the protagonist attempts to sell it regardless, one of Mettaton's soundbytes play.
- ↑ "(O-oh n-no, is that another letter...?) (I don't want to open it...) (C-can't I just slide it back out...?) (N... no... I can't keep doing this.) (I'll read this one.)" - Alphys
- ↑ "Oh my god. Oh no. That's adorable... And I h-had no idea you, um, wrote that way!" - Alphys
|消耗品|| 怪物糖果 ● 繃帶 ● 蜘蛛甜甜圈 ● 蜘蛛蘋果酒 ● 奶油派 / 蝸牛派 ● 雪人的碎片|
Bisicle / Unisicle ● 肉桂兔子 ● Temmie脆片 ● 被拋棄的鹹派 ● 狗狗沙拉 ● 太空食品
方便麵 ● 螃蟹蘋果 ● 熱狗 / 熱貓 ● Glamburger ● 海茶 ● 星光雪糕 ● 傳說英雄
不好的回憶 ● 最後夢境 ● Popato Chisps ● Nice Cream ● 垃圾食物 ● Mettaton臉型的牛排 ● 沉默小狗
|武器||棒子 ● 玩具刀 ● 耐用的手套 ● 芭蕾舞鞋 ● 被撕裂的筆記本 ● 焦鍋 ● 空槍 ● 破舊的匕首 / 真刀|
|護甲||繃帶 ● 褪色的絲帶 ● 男子漢頭巾 ● 舊芭蕾舞裙 ● 陰天眼鏡 ● 彩繪圍裙 ● 牛仔帽 ● 心形墜飾鎖 / 墜飾鎖 ● Temy護甲|
|雜項||集點卡 ● 煩人的狗 ● 狗的殘留物 ● Undyne的信 ● Undyne的信EX ● 神秘鑰匙|
|已刪除||門球捲 ● 石糖 ● 南瓜戒指 ● 無淚洋蔥 ● 鬼果 ● 狗麵冰淇淋|