31 October, the day Alphys dreaded most. Ever since the monsters arrived on the Surface, they have been introduced to various human festivals. In this case, it was Halloween.

Every year it was the same. Alphys would lock herself up in her house and immerse herself in the world of anime. This was to ensure that "trick or treaters" wouldn't break into her house and demand for candy.

The last time Alphys forgot to lock her door on Halloween, Monster Kid and his friends went inside her house and accidentally spilled orange juice on Alphys' comic books. The books were then forever stained with an orange patch.

Alphys was about to close the door when Undyne burst in, waving a letter excitedly. "Alphys, did you get this letter?"

"I- I don't remember receiving it-" Alphys began.

"There is it!" Undyne picked up a sealed letter on top of a pile of unread letters. She handed the letter to Alphys, who took it with trembling claws.

The words, "You are invited!" were written on the envelope in capital, red letters that look suspiciously like ketchup.

Alphys opened it and read the letter. She turned pale. Meanwhile, Undyne was beaming. "Isn't it exciting?" she asked. "We get to have fun in a haunted house organised by a really mysterious person!"

"Y-yes," Alphys stammered. "But I would prefer-"

"Come on!" Undyne took Alphys' claws and practically carried Alphys to the location of the haunted house.

There was a short queue - strangely - to the haunted house. Burgerpants was the ticket manager, and he looked bored as he punched the monster's ticket with a hole puncher.

Mettaton was standing on top of the haunted house - who knows how he got there - and encouraging monsters to go to the haunted house in a loud, booming voice that nearly cracked his microphone.

Suddenly, a deafening, echoey music came on. Everyone stopped talking among themselves and Alphys broke out in cold sweat.

"Ahhh!" came a cry. Aaron burst out of the haunted house while shouting, "Is this my punishment for being creepy?"

Alphys was frozen with terror. Undyne, however, seemed even more hyped. "Don't get cold feet now!" she exclaimed. "We have yet to go in!"

In the end, Undyne dragged Alphys in. The door shut behind them with a frightening bang and Alphys found herself alone.

"See you on the other side, Alphys!" Undyne called.

Alphys began to sweat as she hesitantly took a step forward, expecting something scary to pop up in front of her.

She was trembling as hard as a Temmie. The former Royal Scientist was trying to take deep breaths to calm herself down as she tip-toed along a dark and creepy corridor.

The lights on the ceiling were flickering and every time the light came on for a moment, Alphys would catch a glimpse of someone - or worse, something - at the end of the corridor with a creepy smile.
No! I want to go back! Alphys thought, panicking. She stepped back, only to bump into a wall, realising that she was trapped.

A chilling mist appeared out of nowhere, making Alphys shiver. There was a slow, drawn out creaking sound, causing Alphys to look around frantically.

Something is coming! she thought, paranoid.

To Alphys' surprise, Napstablook appeared from a ceiling trapdoor howling, "Oooo... I'm a scary ghost..."

She blinked and took a deep breath after realising that there was nothing she should be scared of.

"Oh... it wasn't scary?" Napstablook looked quite upset. "Sorry for being such a bother..."

The ghost left, leaving Alphys alone once more in the darkness, unintentionally forcing her to carry on walking forward.
Alphys arrived at a corridor with many strange paintings. Instead of a flickering light, the paintings were lit up by a spooky green light. She trembled in fear, but continued walking.

As Alphys walked past the last few painting, she heard a click. At first, nothing happened.

It was until Alphys heard music. It was different from the one that scared Aaron away, but it was creepy nonetheless.

Gradually, the music became louder - and more terrifying. Alphys' breathing quickened as she tried to block off the music.

The music stopped abruptly. Alphys sighed in relief as her heartbeat slowly returned to normal... that is until she heard laughter.

It was not the type of laughter people make when they find something funny. It was the type of laughter that people make when they are about to... kill someone.

Alphys involuntarily let out a scream and she found herself running - anywhere seemed better than the corridor of eerie paintings.

The laughter only grew louder, which meant either Alphys was running straight into the source of the laughter, or the source of the laughter was running up to her.

Alphys sped up and reached a slightly wider corridor, which was dimly lighted by a few lamps. At the end of it, there was a dark brown wooden door.

The exit! Alphys realised. She skidded to a stop, panting hard from the run. The former Royal Scientist attempted opening the door, but it was stuck.

Alphys was in full panic mode, desperately turning the knob of the door as the horrifying laughter reached its maximum volume.

"Open up!" she shouted, trying to open the door again.

Finally, the door opened, sending Alphys sprawling on the floor on the other side. The laughter stopped and the door closed with a bang.

Out of the blue, there was a round of applause. Alphys looked up and realised that a crowd had gathered around her. Mettaton, in his box form, zipped in front of her and helped her up.

"Ladies and gentlemen, let's give it up for Dr Alphys, who finished the Haunted House race in... 10 mintues and 15 seconds!" Mettaton announced excitedly.
There was a standing ovation from the crowd. Alphys stared at Mettaton, stunned and trying to register what was going on.

Undyne stepped out of the crowd, looking rather proud of Alphys. "I suppose I owe you an explanation."

"Y-you left me," Alphys began, her voice still shaking from the traumatising experience.

"Well, you see..." Undyne started to explain. "We decided to get you to feel more of the world. You have been cooped up in your house for so long, reading anime comics - don't think I am unaware of it - and wasting your life. And Halloween is the perfect time for that!"

"Whose idea was it?" Alphys asked.

Undyne was about to say when another voice broke into the conversation. "It was my idea."

Frisk walked towards them, looking slightly apologetic.

"F-frisk?" Alphys sputtered, shocked.

"I made up the idea and Mettaton did the rest," Frisk explained. "He organised the whole event, asking for help from Napstablook to let him use his music and to get Napstablook in the haunted house itself."

"I don't know what to say," Alphys mumbled.

"Then don't say anything," Undyne said. "Well, I guess that's enough for one night, don't you think so, Alphys?"

Alphys was already bolting back to her house.