Zendaya's 'The Drama' Condemned by Parent of Columbine Victim

Zendaya's dark rom-com "The Drama" isn't in theaters until next week ... and its shocking twist is already being denounced by someone closely connected to a related tragedy.

Here's the deal ... the A24 flick starring Zendaya and Robert Pattinson is being marketed as a fun wedding flick ... but a dark plot twist is shocking the hell out of early unsuspecting viewers ... and the news has spread.

Warning: Major spoilers ahead!

Tom Mauser -- whose son Daniel was murdered in the 1999 Columbine High School massacre -- tells TMZ … he's disgusted the movie's twist is Zendaya's character confessing to her fiancé, played by Pattinson, she planned a high school shooting -- but got cold feet at the last moment.

Mauser -- an outspoken gun reform activist ever since his son was murdered -- says he's completely floored that anyone would think a school shooting would be a good fit for a romantic comedy, even a dark one ... and tells us it's “awful” that of all the shocking twists to make someone rethink their partner … this is where the filmmakers landed.

Mauser tells us ... he was particularly irked by Zendaya recently on "Jimmy Kimmel Live!", where Mauser thought she was laughing off the twist -- as Jimmy seemed to be taking how it would impact some viewers much more seriously.  

Mauser feels the subject in a rom-com starring a beloved actress like Zendaya “humanizes” shooters -- and “normalizes” the shootings. To reiterate ... Z's character did not go through with the shooting -- and mass violence is not depicted in the film.

To be clear ... Mauser doesn't think anyone who has ever considered violence, but not gone through with it, should be condemned -- on the contrary, he's encouraging anyone who has had these ideations to go talk it out with a therapist. However, Mauser doesn't want it to be used for entertainment.