He's a malicious entity that resides within a Virtual Boy, causing those who play his games to go insane and kill themselves in gruesome ways. This has lead to many police investigations; the most notable of which being "The Heathers Investigation".

Goomba BF is BF but he's a Goomba. He has cyan hair, red cap, and yellow shoes.

He turned into a Goomba

Y0SH was built by Omega. Y0SH is similar to Yoshi, with some differences. His color scheme is less saturated and he is a bit scrawnier. His red crest spikes have been sharpened, and also extend to his tail. His hands and neck are covered in a tar-like substance, and he has magmatic cracks on his saddle hump and tail. He has blood leaking out of his eternal smile.

The one named Y0SH

He is specifically from a bootleg pirate copy of Super Mario Land, but his true origins are unknown. He likes to play with his victims, who dare play his game. He can even manifest in his players head, and come into the real world, however mostly chooses not to, as he believes limiting himself makes things more fun.

After years, Luigi develops a hatred for Mario because he was always Mario's shadow and joins Bowser's side in order to kill him.
Luigi appears normally, but with an expression of anger and envy on his face.

Before he died

The Wario Apparition is a vision of Wario's giant, floating, disembodied head. He has brown hair, white manic eyes, blue accents to the sides of his eyes, a pink nose, a zigzagging black mustache, and wears a yellow hat with a blue W on it. In his left pose, his eyes turn into green hypnotic spirals. This also goes for when he starts speaking. He would chase you down a endless hallway until he catches you.

Wario Head

Costume's appearance mimics the original Mario, albeit grayscale and with his eyes obscured by shadow. His moustache appears messier, and his clothes mirror MX's appearance in Mario '85. He's a costume of Mario that will kill anyone.

It's alive!

Turmoil appears as a small version of Mario with large beady eyes, yellow teeth and dark gray gloves. He looks similar to Mario in Super Mario World, but has no overalls button or emblem on his hat. He also has a long Yoshi-like tongue that he sticks out to catch his prey and eat them. He used to be Mario until he accidentally ingested a mushroom containing Yoshi's code. He only kills the ones who have wronged him.

The Goomba eater

Luigi develops a hatred for Mario and joins Bowser's side in order to kill him. However, Mario ends up killing Luigi by knocking him into lava, turning him into a living corpse.

IHY Luigi after he died

L is Real resembles Luigi with a couple of differences, such as vines holding him down and his eyes covered by darkness. Blood leaks from his mouth as he gasps for air, trying to escape the depths of the fountain. He's stuck at the bottom of the fountain and will keep dying and coming back to life until he finds a way to escape.

L Is Real

Stanley's default appearance is the Textureless Mario Anomaly, a version of Mario's model in SM64 but with without his eyes and mustache.

"I'm not having fun."

Omega appears as a tall and creepy version of Tanooki Mario, with a slender body and wearing the same outfit as Tanooki Mario, even having the raccoon tail and ears, which appear fused to his hat. He has a creepy smile, revealing his teeth and singular eye which can change into static. Near his gloves are patches of black fur that run up his arms. He was created by Ultra M to distract you.

 Tanooki Omega

Beta Luigi was Luigi until he failed to save his brother, Mario from the Mansion and then falls into a depressive episode.

Sad Luigi

He appears in Wet-Dry World in the abandoned "Downtown" area where he floats in front of the central plaza. Classified Luigi appears as a floating soulless model of him with no eyes, blood across his body and clothes, and lacking the signature L on his hat, instead replaced with a dark void. He has a different moustache than Luigi as his is straighter and longer, and also lacks a mouth.

From Super Mario 64 : CLASSIFIED

One day, Peach wandered into the forest where she either killed herself or was killed by a mysterious entity. She, or an entity of unknown origin, now inhabits the forest. Coronation Day Peach looks similar to the original Peach, only with black eyes, and a wide smile. She also appears pretty demonic with curved horns, a tattered dress, and in place of hands, growing plants. She also floats in the air.

Again

LG was built by Omega. LG appears similar to Luigi with a few differences. His overall color scheme is much darker, and his bottom half is a melted puddle. His face is elongated and he has a singular eye. His gloves connect to the ends of his shirt's sleeves and the L on his hat is black as opposed to green.

The LG

It is currently unknown how Luigi ended up becoming Mr. L, however, all this seems to be related to Mario and he seeks revenge against his brother. Luigi was Mario's younger twin brother and they lived adventures together, however, several undisclosed events happened that led to Luigi's death when he fell into the lava.

Evil

Boyfriend normally has cyan hair, white shirt with a red prohibition sign, baggy dark blue pants, red shoes, and a red hat, but he's grey with dark shades of black. He's not really scared of anything until Girlfriend or someone in his family is in danger of what ever is there and that's when he realizes that it's serious.

Boyfriend from The End

 As the normally unseen host of Mario Party DS (and a strange offshoot of MC Ballyhoo from Mario Party 8), he resides in pirated copies of the game as a secret impossible boss in order to teach pirates a painful lesson.

 The Host

Beta Mario is a depiction of Mario after his fate was sealed by King Boo. He's a figment of Beta Luigi's depressive imagination, being a dramatization of the green plumber's brother's misfortune caused by King Boo. Beta Mario has pale skin, blank white eyes surrounded by black shadow, and faded clothing. He's encased in a faded brown framed portrait with a dark blue glow surrounding it.

He's stuck forever

Super Bad Mario is a version of Mario from the titular YouTube series by Pastek, in which Mario is edited over various fail videos to make it seem like he caused them. Super Bad Mario directly uses Mario's Super Mario World sprites.

The funny guy

Basically he sits in a room decked with a headset, streaming. He has a red cap, cyan hair, t-shirt with the prohibition logo, red shoes, and his blue pants.  You're his best friend.

Man started streaming

The three boys

He has two forms, his False Hero form and his true form. He's 6 feet in his False Hero form but he's 12 feet in his true form. He is found sitting within an abandoned copy of Super Mario Bros and MX takes the souls of those who play the game so that he can "play" with them for all eternity.

False Hero-MX

Promotion Mario appears as a 3D render of Mario behind the stand hosting Nintendo Mania. He has the same attributes from his original appearance aside from having a bigger moustache and a very friendly look on his face holding a mic up in the air. When Luigi appears in the TV, he loses his happy smile and instead stands still with an unchanging, yet seemingly depressed, blank stare. He's known for hosting the hottest new video games.

Promo Mario

W4R was built by Omega. W4R is similar to Wario, with some differences. His color scheme is less saturated and he has a more creepier appearance. He has a lot more teeth and his mouth is melting, and he has a black W on his hat drawn on with ink. His gloves are much longer and merged with his sleeves. His mustache also points upwards more.