I gotta say, Hotland is the worst part of multiple playthroughs. Alphys's constant natter is annoying enough, but these not-actually-dangerous interactive cutscenes are irritatingly time-consuming.
Fun value 61 gives a chance to reveal this guy. He's missing his own face, mostly, but holding someone else's...
Gaster Follower:
Alphys might work faster.
But the old Royal Scientist, Doctor W. D. Gaster?
One day, he vanished without a trace.
They say he shattered across time and space.
Ha ha... How can I say so without fear?
I'm holding a piece of him right here...And with that, he's gone. I'm not sure he was holding someone else's face, now... since it was the face in the guy's hand that did the talking. Weird. Eerie.
Fun value 62.
Gaster Follower:
After all, the old one... Dr. Gaster. What an act to follow! They say he created the CORE. However, his life... Was cut short. One day, he fell into his creation, and...Talk again:
Will Alphys end up the same way?Fun value 63.
Gaster Follower:
The previous one... Dr. Gaster. His brilliance was irreplacable. However, his life... Was cut short. One day, his experiments went wrong, and...Talk again:
Well, I needn't gossip. After all, it's rude to talk about someone who's listening.Fun higher than 90.
Goner Kid:
Have you ever thought about a world where everything is exactly the same... Except you don't exist? Everything functions perfectly without you... Ha, ha... The thought terrifies me.You can hike through Waterfall to bring Goner Kid an umbrella for a different script.
Goner Kid:
Ha, ha... You know, that does make me feel a little better about this. Thank you. Please forget about me.This is also when I discovered that holding the umbrella while talking to the Nice Cream Man will give you a discount.
Fun 65 allows a secret sound test that replaces the fishing rod area in Snowdin. There are only four songs, none of which play in game and most of which... uh, aren't actually songs. There's
Happy Town, and
Meat Factory, and
Trouble Dingle... I'm sure there's some sort of musical Easter egg hidden in them, somewhere, but to my knowledge no one has actually found one. The interesting thing of note here is the last track:
Gaster's Theme.
The sound test wraps, and drops you back in the fishing rod area, with this message.
Okay, this one isn't attained through a Fun value, it's from manually editing the room you spawn in when you load the game. The text that prints is in Wingdings, making it... uh, largely illegible. And making its writer undoubtedly the "man who speaks in hands" the riverperson warned us about so long ago. But if you transcribe it to something legible, you get...
JOURNAL NUMBER SEVENTEEN:
DARK DARKER YET DARKER
THE DARKNESS KEEPS GROWING
THE SHADOWS CUTTING DEEPER
PHOTON READINGS NEGATIVE
THIS NEXT EXPERIMENT SEEMS VERY VERY INTERESTING
...
WHAT DO YOU TWO THINK?The music, such as it can be called that, doesn't appear on the soundtrack but is referred to in the game files as
smile.ogg. Why "smile"? Well, feed it through a spectrogram and some of the images you get look like
a creepy face...And, finally, Fun value 66. This causes the "fake hallway" to appear near one of the save points in Waterfall.
With a ten percent chance of the hallway containing a gray, washed-out door on one wall. I'd like to apologize to everyone who was on Steam while I was taking the screenshots for this update, and the constant deluge of "nosimpleway is now playing Undertale" prompts that popped up while I restarted the game a dozen times trying to get this proc.
Oh, yeah. This hallway, and the three Followers, the sound test, and Goner Kid all set your Fun value to 0 once you pass through the rooms they spawn in, whether they actually appear there or not. So you have a 1 in 100 chance of getting the Fun value correct, then a percentage chance between 10 and 50 that the special event happens. There's only one shot at it per playthrough, unless you're manually editing the files like I am, and that requires quitting and restarting. So, sorry, Steam friends.
Oh, ranges between 67 and the Goner Kid are what spawn Suzy's neighbor in the Quiet Area in Waterfall.
Anyway.
Inside the room is... this guy.
He seems pretty surprised I found him, before he fades from view with the same sound effect as the first Gaster Follower.
This guy is referred to in the game files as simply "Mystery Man" but is assumed by the fandom to be W.D. Gaster himself.
So.
Up until the January 20 patch, Gaster had been completely dummied out of the game, too scattered across time and space from falling into magical/geothermal engine of the CORE to have any chance to appear during play. Needless to say, the Undertale fandom completely lost their collective shit upon his discovery. And now with the patch un-dummying Gaster back into the game -- albeit at vanishingly rare odds -- the weird conspiracy theories have gotten even more complex.
That's all the game has to say about Gaster himself. But there are a couple implications to consider:
The caller who sings the Wrong Number Song asks for someone whose name starts with G. Someone who can't find Gaster's number makes a lot more sense than someone mistakenly calling for Gerson. Or, uh, Gyftrot.
Gaster wrote Journal 17 in a whimsical font. The only other characters in the game who do that are Papyrus and Sans, who speak in the fonts they're named after. And it's quite likely that the W.D. in Gaster's name stands for "Wing Dings". Exactly what Gaster's relationship to the skelebros is remains unknown, but it certainly there. And if the Mystery Man is Gaster, his head could well be a cracked, broken skull with the teeth knocked out.
Or just an oblique reference to Uboa from Yume Nikki. Hard to tell.
Those skull-headed cannons that Sans whips out when you fight him? The game files refer to them as "Gaster Blasters". And Sans loves of science fiction ("especially when it's real"), keeps an infinite loop of quantum physics and joke books on his coffee table, and has unreadable blueprints to a mysterious device in his basement. And while I'm not knowledgeable enough about music to confirm or deny that it's definitely the case, it sounds an awful lot like the four-note sequence of Gaster's Theme serves as the bridge between the Sans theme part and the Bonetrousle part of
The Song That Might Play When You Fight Sans, a piece of music that's just as dummied out of the game as Gaster himself was previously.
Who is the "you two" referred to in Journal 17? Asgore and Toriel, Gaster's employers in his position as Royal Scientist? Sans and Papyrus? Is Alphys one of them? No clarification exists.
Other than those implications, who can say? Fandom theories abound, but canon is hard to come by.