They  went through the door and there was an orange ghost that tried to attack them

All of a sudden something sucked up the ghost and it turned out to be an old man in a lab coat with something on his back. He tried to get the ghost and the ghost dragged him around for a while until the ghost hit him which knocked him back.

“Ouch.” the man said. “Ooof. I sure take a lot of knocks in this line of work. I’m getting too old for this ghost-catching tomfoolery. Anyway, nice to meet you. I’m Professor E. Gadd. This house… I swear it has more ghosts everyday! What’s a young feller like you and a horse doing around here, anyhoo?”

All of a sudden three orange ghosts appeared. “Uh-oh! This looks ugly.” Professor E. Gadd said. “ All right, youngster, look lively! Follow me, posthaste!” Then he took them out of there and took them to a shack.

“So your name’s Luigi and the talking pony’s name is Fluttershy?” he said. “I think our paths were destined to cross.”

“Umm w-where are we?” Fluttershy asked.

“Hmm? Where’s this, you ask?” he said and Fluttershy nodded. “Why these cozy quarters are where I do my ghost-studying. Professor E. Gadd’s Ghost research laboratory. The lab, if you’re of shortening mind. So let’s see if I got this straight, Luigi. You won a mansion in a contest you didn’t even enter?” Luigi nodded and then Professor E. Gadd started talking again. “Sounds pretty fishy to me. So you believe the mansion actually exist?”

“Yeah. Why?” Luigi said.

“Strange. I’ve been living here since I was a lad of twenty or so, and I’ll tell you that mansion appeared just a few days ago!” Proffesor  “The spirits have fooled you! I don’t know if it’s a dream, an illusion, or what-all, but I surely wouldn’t be too happy winning a haunted house! Now that I get a look at you, Luigi, I just recalled a guy with a red hat just like yours went up to the mansion without even stopping to chat, and he never returned. Was he a dream too?”

“I think you might be talking about my brother, Mario!” Luigi quickly said.

“What? That guy was your brother? Oh no! That’s horrible! He wouldn’t stand a chance against the ghost without my help! You have to go after him! Here’s the plan: I’ll teach you and Fluttershy if she’s helping you how to deal with ghosts so you can rescue your brother, Luigi. It’s a good thing I have an extra Poltergust 3000 so both of you can use one. Poltergust 3000 what this vacuum cleaner is.”

Professor E. Gadd took them to training rooms and then trained them about how to catch ghosts.

After that they went back to the mansion. There they noticed a toad crying. But Fluttershy had no idea what it was. The toad cried “Boo hoo hoo! Where did you go Mario? Waaaaah! Wah!” then Toad noticed Luigi standing in front of him. “Huh? Luigi?” He said. “Waa… Wow! It’s Luigi! You finally made it! Oh joy! Thank goodness!”

“Hi toad.” Luigi said “What are you doing here?”

“Me? Well Princess Peach asked me to come here to look for Mario. He left when he heard that you’d won a mansion, and he never returned! Th-then when I arrived here, the mansion was full of ghosts, and I didn’t see Mario anywhere, and I kind of freaked out a little, and I didn’t know what to do! It’s been awful! Please, please, please, you HAVE to help me find Mario! If he doesn’t get back, you have no idea how upset the princess will be! She’ll flip!

“Leave it to me!” Luigi said. (And yes I am just copying what they said in the game to this fanfic.)

“Yay! Thanks, Luigi! You made my dark and stormy night! By the way who’s that pony over there?”

“Hi! I’m Fluttershy!” Fluttershy instantly said, due to how cute the toad was. (I made her think toads are cute because it’s in character and I think the toads in the Mario universe are adorable!) “What are you anyway?”

“I’m a toad. Toads are creatures that live in the Mushroom Kingdom. I wish there was a way I could help you two.” (In this fanfiction since there’s no saving games the toad is pretty much useless.) Then they decided to walk into the room that was unlocked. Next Chapter: Ghostbusters Estimated time remaining: 22 Minutes