Mandy had plans of conquering the world, but one day Billy moved away and everything changed. Stopped. Live kept moving forward and nothing was ever quite the same. Years later, Billy moves back and misadventures ensued.

A flapper is being reaped by the grim reaper

when Santa turns into a vampire Billy and Mandy team up with angry Luigi and alem tuber to find the main vampire

Gender Flipped, Dumb Luck AU! What if Mandy was the one who was cursed with bad luck?

An alternate universe fanfic where Billy never met Mandy or the Grim Reaper.

What starts out as just another regular day in Endsville turns into one of adventure for Grim, Billy and Mandy when they find themselves in the middle of another multiversal takeover plot led by Aku and Vilgax! Just like before, the two-headed robot is looking for heroes, but Grim, Billy and Mandy decide to test the robot's worthiness in the best way they know how.

when Billy fights with Jeff he now has a choice go home or save his friends based on wrath of the spider queen

Mindy's mom hired a tutor to help her daughter study well.

Much to their strong dismay, LJ and Zofia have to go to the Underworld with Billy, Mandy, and Grim when the death reaping skeleton is sentenced to court for misusing his powers and the Boogeyman takes him to court. When Grim's powers are soon taken from them, they are told about Horror's Hand which can make one's fears come alive and Boogeyman intends on taking it for himself.

Billy and Mandy realize they have old versions of themselves from 1998 and go to visit them. Grim realizes that he's better off with the normal Billy and Mandy.

When Junior first came to the surface world, he stole the appearance of a young boy at winter camp. In doing so, he unknowingly tore that boy's family apart. OC centric

Mandy meets a goth girl named Mariella after getting wide hips.

Ever wonder what happened to Underfist after the movie? Read to find out! PS. Cartoon Network, please renew Maxwell Atoms's contract and make this a TV show!

Billy and Mandy are in High School now. While some parts of there relationship has changed, the Fundamentals are still the same. BillyxMandy, one shot.

LJ, Zofia, and their friends come to celebrate Halloween with Billy and Mandy. However, not all is well when Grim tells them the story about a prankster known as Jack O. Lantern who lived in ancient times, causing tricks for people. Due to Billy's stupidity, he comes back and takes Grim's scythe to make it Halloween night forever so he can conquer the world.

As they settle into married life, Nergal decides to reveal to Sis the story of how he grew up and how he came to be banished from the Underworld. In the meantime, the powers that be threaten their future ... a future Sis is keeping a secret for now.

They've faced down an evil marshmallow bunny, squid attackers from the underworld, aSTRoVaMPiReS, and spiders. They've grown close...er. They're accepted as Earth's heroes...kind of. But now, Underfist faces its greatest challenge yet...the judicial system!

Mandy finds out that she has a voice of a angel.

Grim found out that Mandy is dancing.

LJ and Zofia start going to school with Billy and Mandy, but luckily, their friends Dib, Gaz, Nergal Jr, Kimberly, Chrissy, and even Akito and Estelle will be going with them. It's not a very good first day of class though since there's a spider infestation, and it turns out that the school is going to be held for the Spider Queen for her revenge against the Grim Reaper.

Billy and Mandy are teenagers when they accidentally got transport into the Underworld where they must find a way out before the Boogey Man and Nergel will take over Endsville.

Based on the SpongeBob episode "Rock-a-Bye Bi-Valve": Billy and Mandy are older now, and find an abandoned child. With no one to take care of him, Billy and Mandy decide to raise him as their own. But with Billy constantly working and never giving Mandy her break, tempers start flaring around the odd couple. This fanfiction is only BillyxMandy if you want it to be.

A followup on "The Secret Snake Club." Irwin is released from jail and meets up with a certain macrame club member. A CarolxIrwin oneshot. Request fic.

In this story, Mandy decides to give a very special Halloween treat to someone who helped her on her first Halloween.

Only the journal entries can show the true killer. Billy, Irwin, Mindy, Nergal. . . . . Oh, who could it be if its even one of them.