Twila Beatiful Psyco Topaz Cullen was a Mary Sue in "Twila The Girl Who Was In Luv With A Vampyre", a badfic in the Twilight continuum. She was eventually outed as a troll, and slain by The Fisherman and Agent Evie. She is an obvious alternate-continuum clone of Ebony Dark'ness Dementia Raven Way.
Twila has little to no characterization beyond being a 'goff' (essentially a strongly stereotypical emo). She is described as a vampire (in the sparkly sense), and lives with her sister and fellow vampire, Midnite.
She attends the same high school as Edward and Bella, wins Edward away from his canonical partner within a day and then heads off to meet his family. Due to her strong Suvian influence, the entire Cullen clan become instantly attracted to Twila and there is a brief fight over her. They then attend a My Chemical Romance concert for no discernible reason.
After getting married in an 'atheest ceremoni' (which, due to poor spelling, took place inside a giant hosepipe) to Edward, the couple agree to murder Bella Swan. They do so, and then proceed to eat her bed in order to hide the evidence.
After the troll entity had been exorcised from Twila, it was charged with "wilfully and maliciously perverting the Twilight canon, having a grasp of the English Language that a three year old would be ashamed of, the use of inane internet slang in writing, directly addressing the reader without cause, using author’s notes within the text, causing massive temporal compression, having a stupidly overdescribed appearance, being a vampire for no good reason, having no characterisation beyond being an ‘emo’, having no understanding of atheism despite claiming to be an atheist, creating confusing and ridiculous scenes involving the Iranian President, holding a wedding inside a giant hosepipe, reducing the characterisation of all characters besides the Cullens to that of ‘prepz’, having characters share your taste in music and fashion for no good reason, having characters teleport for no good reason, causing Edward Cullen to fall in love with you, causing all other Cullens to be attracted to you, breaking up a canon relationship, trivialising self-harm and murder, killing Bella Swan, compressing the geography of Forks, being friends with a supposed creator deity, eating an item of furniture, the creation of an as-yet-unknown number of minis and bringing a new meaning to the phrase ‘irritating PPC agents’".
The exorcised troll was rather large, and thus the Fisherman had to return to the Armory at HQ to obtain a weapon capable of killing it. He returned with two Covenant plasma weapons, a repeater (which Evie used to distract the troll), and a particle sniper rifle (which the Fisherman used to shoot the troll in the head). The body was atomized by overloading the repeater to cause an explosion.