Chapter 21 has a little throwaway joke where The Overseer uses the word "succor" while talking to Flowey and Frisk, which they puzzle over afterwards. That little joke always tickled me (maybe because it shows the childlike Asriel still in Flowey) so I wrote an epilogue based entirely on that scene. But in the end I decided it pulled the focus away too much from the main characters and the actual ending of the story, so I decided not to include it.
But now, after waffling on it some more, I've decided just to throw caution to the wind and put it back in as a "deleted scene". Make of it what you will! And thank you for reading.
Several days later…
The whirring motors and humming machines somewhat muffled the strains of Holst's St. Paul's Suite playing over hidden speakers, but the scientist hummed along anyway as he used a claw to move the slider on the magic oscilloscope and reposition the phase. He turned and floated over to another table, swaying along with the lively violins as he checked the magical reactions taking place in a set of sealed canisters.
With a sudden ding, the music stopped. Doctor Gaster raised his head. One of the screens mounted to the wall had lit up.
(1) NEW UNDERMAIL RECEIVED (DBOX ATTACHMENT)
He moved towards the screen with interest. He had signed up for an UnderNet account just a few days earlier (with a suitably unremarkable account name) and only a few people knew his address. He doubted it was his new turtle monster friend, though he appreciated the effusive and somewhat rambling message of gratitude the old fellow had sent. That just left a handful of possible correspondents, all of whom were in the same household. The screen filled with text.
FROM: Aerizel -at- ebottvalley . unet
TO: LabDoc -at- ebottvalley . unet
SUBJECT: Hello!
Hi, Doctor Gaster! It's me, Asriel! I wanted to write to you and say thank you again for everything you did for me and Chara! It's really nice to be back home with Mom and Dad! We've got some new beds and stuff, and Mom's going to take us shopping to get some clothes and toys and other things. It's going to get busy soon because Mom is already telling us that we've got to start going to school. :( :( :( Chara said that we shouldn't have to because we're like a million years old, but Mom just laughed and said we still have to. Frisk says the school's pretty fun, though. Anyway, we'll be coming back up the mountain soon to pick up more of our stuff from our old house, so we'll come by and say hi when we do! Also, we remembered that you like these (check the box!) so we wanted to send you some to say thank you. I hope you like them! We'll see you soon and thanks again!
Love,
Asriel
The scientist's face crinkled in a smile. He stepped over to the counter directly beneath the screen, where an empty metal frame was mounted upright with several wires connected to it. He looked up at the screen again. A green button under the message labeled "DBOX ATTACHMENT" pressed itself. At the same moment, a flash filled the empty center of the metal frame. When it faded, an inky black void was left.
Doctor Gaster had been very impressed when he searched through the records of his successor and discovered her specifications for interdimensional storage. The technology itself was incredible, but the fact that she had been able to incorporate dimensional boxes into a phone app was an astonishing feat of engineering. With no suitable phone of his own, he had constructed his own interdimensional portal, making sure that it was compatible with the UnderNet.
A delicate claw reached down from the ceiling and pushed itself into the black void. A look of concentration came on the ghost's face as the claw rummaged around. Finally, it withdrew and deposited a number of items on the counter.
With a puzzled expression, the scientist bent over and studied the small, colorful discs that had come out of the void. They appeared to have small handles for manipulating them. The claw picked up one by its handle and held it out towards a scanning device that descended from the ceiling. An analysis of the disc's composition appeared on an adjacent screen. The doctor's bewilderment grew. He racked his brain as he thought back to the chaotic events that had taken place a few days earlier, but try as he might, he could think of nothing that correlated these gifts with his time spent with the Prince.
With a shake of his head, he turned his attention back to the screen. The text cleared itself and a new message began to appear.
FROM: LabDoc -at- ebottvalley . unet
TO: Aerizel -at- ebottvalley . unet
SUBJECT: (With Regards To): Hello!
May it please your highness,
I am delighted to hear that you are well and thriving in your new home on the surface, along with the rest of the royal household. I am also deeply humbled that I was permitted to play a role in the restoration of your person along with her highness, the Princess. I trust you will find your schooling invigorating, and should there be an occasion for you to come to the CORE again, I would be most gratified by your visit. I would be very grateful if you would convey my regards to their majesties the King and Queen as well as to your esteemed brother and sister. Please also accept my thanks for this gift that you have graciously sent me.
Your humble servant,
W.D. Gaster
Royal Scientist, (Ret.)
With a whooshing sound, the message disappeared off the screen and the orchestral suite resumed playing through the speakers. The scientist floated around the room checking various desks until he found what he was looking for. A claw picked up an unused mug, and within a few moments the discs had been placed in it, handles facing downward, and carefully arranged.
Humming to himself, the scientist returned to the oscilloscope and began adjusting the amplitude. On a shelf above the equipment, the claw gently placed the mug. The young Prince had a kind heart, thought the scientist, even if the meaning of his gift remained a mystery. If nothing else, the garish swirling colors of the suckers made the room look a little more cheerful.