Depiction in the Series
In the beginning of the episode Power Ponies, Spike shows Twilight Sparkle a couple of pages of a Power Ponies comic book on which the Mane-iac is depicted. Spike refers to her as the Power Ponies' "most evil nemesis." Spike says that she used to be the power-mad owner of a hair-care product company until she accidentally fell into a vat of green liquid and was electrocuted by a downed power line. The accident gave her strange new powers—such as a prehensile, stretchable mane—and caused her to go insane. Another page shows the Mane-iac breaking into the Maretropolis Museum and stealing something called the Electro-Orb. When Spike and his friends are sucked into the comic book world of Maretropolis and become the Power Ponies, they witness the Mane-iac steal the Electro-Orb from the Maretropolis Museum. The Power Ponies confront her, but she watches in amusement as the Power Ponies struggle to use their newfound superpowers before leaving the scene with the orb.
The Power Ponies track the Mane-iac to her headquarters at the abandoned shampoo factory and defeat her henchponies in a battle. However, the Mane-iac uses her "Hairspray Ray of Doom" on the Power Ponies, freezing the ponies in place and rendering their powers useless. She then takes the Power Ponies prisoner but leaves Spike/Hum Drum alone, considering it pointless to capture him.
Inside the factory, the Mane-iac uses the Electro-Orb to power her doomsday device, which resembles a cross between a large pink blowdryer and a cannon. The Mane-iac says she will use the cannon to amplify the power of her mane by "one million times", expelling an energy blast that will cause everyone in Maretropolis's mane to grow wild. As she gives her victory speech to her followers, Spike traps some of her henchponies and helps in freeing his friends. Just before the Mane-iac can use her weapon on Fluttershy/Saddle Rager, a firefly enters her line of fire, and she swats it. This action angers Saddle Rager, transforming her into a powerful muscular pony. The Mane-iac fires her doomsday device at Saddle Rager, but the beam reflects off Saddle Rager and hits the Mane-iac instead. Saddle Rager destroys the doomsday device, and the Mane-iac's mane grows out of control, wrapping around her like a straitjacket.
The Mane-iac is shown to behave in an evil and unhinged manner, expressing delight at the prospect of oppressing Maretropolis. She sneers at the Power Ponies when they fumble with their newly acquired superpowers. The Mane-iac thinks very little of the Power Ponies' sidekick, Hum Drum, even deciding not to take him prisoner with the other heroes. She is also portrayed as sadistic and cruel, claiming that the Power Ponies only keep Hum Drum around because they feel sorry for him and calling him useless. Much like her name is a pun, she often uses puns when she speaks.
Role in the series
While she appears to just be fictional, Mane-iac gains a major role in the series. Apparently Spike's comic adventure made Mane-iac feel foolish for ignoring what was nevertheless her downfall all because Humdrum was worthless in the past until now, and as of now Humdrum has become more than just comic relief and is a more well-developed character, everyone criticizing his role in the comics. Thus when her incompetence made her a laughing stock to be replaced with villains like Dr. Calamity, a pony Doc-Ock that aims to rule everything he can get his Doc-Ock claws on, Dominotaur, A Minotaur Super-Villain in the theme of Dominos known for acts of destruction domino sytile, Steelmill Beak, A griffin crimeboss with a beak made out of every single metal in existence, Hy-Dragon, a mutant Dragon/Hydra Hybreed created from a rouge secret millaterry faction where each head is deadly enough on it's own but a combined blast has the destructive radius of 100 atom bombs, The RAIN-Deer, a rouge sentient deer with weather malmitulation aiming to punish pony kind for dominating what once belong to her people, Mr. Chimeras, The once valued political friend of the power ponies until falling victim to an unstable mutogen from Calamity that gave him the power to become any creature he can think off but corrupted him in the progress, Professor Ponysaur, A once beautiful unicorn who turned herself into an Deinosaurus in her aim to restore the "Glorious Age of the Saursus (Equestian Dinosaurs) since only a handful exist in isloted parts of Equestia, Jackass-In-A-Box, A donkey super-villain who was once an abused toymaker until a terrorable accsident redused him to the state he is in now, and being deemed a monster by those he had loved, he went Joker-like insane and became "The Jackass of Crime" with the appearence no less different then the boss from Donkey Kong 64, Teddy Ursa Major, A once normal teddy bear fused with the DNA of the Ursa Major condemned the now sentient toy to a life of misery and villainy in being robbed of his calling in life of being a cuddly toy, Outcast, A disgraced superhero turned villain who grew jealious of the Super Ponies growing into fame and turned villain for the sake of trying to get rid of them in alou of being the pony equilient of Captain Qwark, Mix-Match, a rouge Draconaquus plotting to induse chaos to both the comic world and a repeat breaker of the forth-wall who plans to turn ponies into fellow Draconaquui, and finally but not least, Bayou Skales, a cajun speaking voodoo mastery dwarfed Baskilisk that wants revenge on all of Equestia and Princess Celestia (Comicverse) for banishing his kind in Tartarus, she realizes that she exists in a fictional world thanks to Spike accidentally combining the magic of his comics to those of the comics published by the Superiors. Realizing that there was a much bigger world to rule, and that Spike is the one who changed Humdrum, she manages to convince all villains of both XD Comix and Generation Comics to join forces and become a bigger force to get revenge on Spike, and take over the UUniverses. But with help of the Shell Lodgers, the heroes of the comics are able to stop this comic-book chaos and banish Mane-iac back to her world. Though she doesn't give up now that she knows there's a big world that is ripe for the taking.