Inspired by Dr. Jekyll and Mr. Hyde and Family Matters characters Steve Urkel/Stefan Urquelle. A scientist makes a serum that makes him into a new but dangerous person attempting to win a woman he's obsessed with. 

I suppose remembering that show I wonder what if the serum turned Steve into a monster instead. 

SYNOPSIS:

THE DEADLY OTHER ME

August “Auggie” Cotton is a young aspiring academic and is madly in love with Esmerelda “Esme” Morales, and claims he is her boyfriend and declares his love for her. But she is in love with David “Davis” Cole and dates him instead. Auggie is convinced that in order to win Esme he needs to become someone else and seeks to create a serum to make him into a suave and strong and irresistible ladies’ man. Years later Auggie is nearing completion of his serum and works at a medical company giving him the time and benefits and sources to work on his serum in his spare time while working on new medications. He still loves Esme and views Davis as beneath her and not good enough for her. Auggie completes his serum testing it on some of the lab animals loaned to him by his boss and former mentor Dr. John Giles who along with his other employers are unaware of his own secret project. But when he leaves prepared to use it on himself, he does not see the animals he tested it on turn violent and aggressive, and using it Auggie turns into Austin Colt. Unrecognized by Auggie’s neighbors Austin visits Esme and Davis in secret and meets and befriends Esme, and makes a connection with her, but when he returns, he sees one of his female neighbors and charms his way into her house, Austin rapes and kills her. Austin turns back in Auggie with any memories of his time as Austin passed off as dreams. But communicates with Austin through video recordings and Austin does the same with Auggie.

Auggie desperately tries to perfect his serum and become Austin permanently and continuously takes it, but unknown to him Austin Colt is a violent sociopathic man and soon becomes a serial/spree killer as well as a drug dealer and rapist, his desperation effects his work, and Giles wants to find him after finding the lab animals seemingly abused and some dead. While keeping his criminal life secret and begins a connection with Esme driving a wedge between her and Davis, but soon Auggie learns of Austin’s criminal life and that Austin intends to take over and make Esme his own. Then as Austin he attempts to seduce her and win her love, but she turns him down affirming her love for Davis, but then Austin loses his temper and attempts to force himself onto her and rape her but is saved by Davis. Austin flees and as Esme testifies to the cops, they realize Austin is the criminal they have been looking for, when Austin is unable to gain access to his lab, he sends a message to Dr. Giles to acquire them for him, Giles returns with Davis, and they demand to know where Auggie is and with no choice Austin turns back into Auggie and reveals everything.

Giles informs Auggie that he has taken the serum to many times and now he turns into Austin Colt without it, and that Austin is taking over and that Austin represents the negative aspects in a person and is turning into a monster, Giles upset and disappointed in his unethical experiments and deceptions Giles fires Auggie. Auggie goes to Esme to tell her the truth of what he is turning into, and she does not believe him until he turns into Austin and kidnaps her and kills a policeman. Giles and Davis realize what is going on and take the cops to Auggie’s.

Meanwhile Austin turns back into Auggie and Esme tells Auggie why she fell in love with Davis over him and how she only viewed him as a friend until he created Austin Colt. Giles, Davis and the police arrive Auggie tries to trick them, but Giles, Davis and Esme expose him, and he turns into Austin Colt and attempts to escape and kills Giles but is killed trying to escape and turns back into Auggie.

The danger passed, Davis and Esme marry.