Mona Vanderwaal - Original "A"

"You're not the only genius in this car. You bitches underestimated me"
- Mona

What's the story behind the first antagonist of the show? You're about to find out!

Mona Vanderwall has been bullied over the years by Alison DiLaurentis and her friends. She was nicknamed "Loser Mona". With Alison's disappearance, Mona and Hanna became close friends and went from being an outcast freak to a popular  and pretty mean girl. With this, she started to send texts harassing and manipulating the girls after Alison's funeral. She acted the way she did because of the fear she had of losing Hanna, who was at the moment her only friend. She thought that the girls were trying to separate them, and this feeling drove her actions. Later on, she was diagnosed with a personality disorder and was admitted to Radley Sanitarium to get therapy. After being discovered, she was also a target for the following A's, forced and tortured. When the girls escaped from the Dollhouse, she helped them to unmask A, trying to put an end to the game she started.

This is more or less her story. But what is she known for? 

She protagonized the first two seasons, hiding herself after A's nickname and wearing a black hoodie and a pair of black gloves, blackmailing the girls. During these two seasons, she had plenty of time to humilliate and manipulate the girls, both being Mona and being A:

- As Mona, she trashed the letter Caleb wrote to Hanna before leaving, asking for forgiveness.
- As A, left false clues for the girls to spoil the path that would lead the girls to Ali's killer, such as the bloody trophy.
- As A, tried to make public the relationship between Aria and Mr. Fitz.
- As Mona, bullied and nicknamed Lucas. She did to him the same Alison did with her.
- As A, sabotaged the fashion parade the girls did in Ali's memory, wearing her dresses.
- As A, forced Emily's homosexuality to go public with some photos with Maia.
- As Mona, dated several guys in order to confuse the girls. 
- As A, kidnapped the therapist Dr. Sullivan.
- As A, she ran Hanna with a car, at Mona's camp.
- As Mona, she corrupted and manipulated Hanna into shoplifting 
- As A, she messed with Ian's death, pretending that he was still alive.
- As A, she played with Em's scholarship, faking it.
- As Mona, she was constantly fighting with Spencer over leadership and good grades. 
- As A, she told Ella Montgomery about Byron's affair with Meredith, blaiming Aria for not telling her. 

Some of this information has been taken from Pretty Little Liars Wiki Fandom, but there's still a lot that you can find out by yourself, if knowing too much doesn't put you in her sight...

I could continue framing this evil character, but I think you can make a point of who she really was during these first two seasons. Here I leave you a video of the last episode of the second season, where the girls find out that Mona was playing A. 

Lucía Alderete