Sheldon "Shelly" Finkelstein  was a character in Friday the 13th Part III. As an overweight prankster with a "Jewish Afro" hairstyle, Shelly was self-conscious about his looks. He pulled pranks on his friends so that he wouldn't feel like a "nothing". Shelly was notable for being the owner of Jason's original hockey mask, as well as being Jason's 18th victim.
In 1984, Shelly Finkelstein was a student at a prestigious university and the roommate of Handstand Andy. Shelly was also a horror aficionado. Being a fan of the genre, and mainly serial killers, Shelly was a collector of their many masks. It was known that he played goalie for his local hockey team and kept the mask. Due to Andy's girlfriend Debbie being the best friend of Higgins Haven proprietor Chris Higgins, the two were invited there, along with stoner couple Chuck and Chili and Vera Sanchez, to the Crystal Lake backfront for a weekend of idyllic fun and partying to help ease Chris Higgins' fears of an attack two years prior by a violent deformed monster of the woods. Beforehand, Andy gets him a date for their outing to Higgins Haven, a resort at Crystal Lake but Shelly believes no girl especially one like Vera would go out with him being himself when he didn't have the looks to complement a gentleman personality.
Shelly agrees to go to Higgins Haven with a group of wild friends of Chris Higgins. Shelly was introduced by his roommate Andy to his blind date for the weekend: the beautiful Vera Sanchez, to whom he instantly becomes attracted. On their drive to Crystal Lake, Shelly criticized Chilli and Chuck's activities and claimed there are better things to do with life then smoke dope. While still on their way there, the group had panicked when the police trailed not realizing they were only trying to pass to get to the crime of Harold and Edna Hockett murder. The group was forced to scoff down the marijuana but Shelly declined to swallow any of it. The group stops the van due to an old man sleeping in the road. He shows them his "omen" which Shelly identifies as an eyeball and he quickly takes off with the rest in the van.
When they arrive at Higgins Haven, Shelly faked his murder by applying prosthetic blood, and wearing a fake ax on his head, angering the group. Chris discovered Shelly and then immediately start to not like him for his cruel prank labeling him as a creep, even though Shelly apologizes saying that it was just a joke. Vera shows little interest in Shelly at first but agrees to go to town with him for groceries in Chris' boyfriend Rick's car. Shelly begins talking to Vera and the two start up a friendship. After being harassed by bikers in the grocery store, Shelley's wallet was given to Vera because she forgot hers. The bikers Ali and fellow friend Loco then grabbed Shelly to prevent him from helping Vera but was too afraid and intimidated by the them that he simply offered them a beer. Ali had stepped outside and in panic Shelly reversed accidentally mangling his motorbike. The bikers attacked, smashing the car's windshield. Shelly shows courage and gets revenge on them by running over their motorcycles while driving away from the store.
When Shelly returns to Higgins Haven, Rick becomes angry at the damage done to his windshield by the biker's attack but Shelly explains that it wasn't his fault and hands the remaining change from the grocery store to him. Vera soon warms up to him. Vera rejoining the group went skinny dipping with them Shelly refrained claiming of his unattractive appearance and obesity shouldn't. Afterwards during the night, Shelly tries an unsuccessful advance on Vera but is rejected. That night, Shelly juggled fruits with Andy in a competition but won by forfeit as Andy went upstairs to consummate with Debbie.
Angered by Vera spurning him, Shelly later sneaks up on her at the Crystal Lake dock, wielding a harpoon while wearing a wetsuit and hockey mask, intending to scare her. After being frightened by Shelly, an enraged Vera tells Shelly that she would like him more if he did not act like a "jerk," which Shelly responds by saying that "being a jerk is better than being a nothing", but Vera says that he is not "a nothing".Put out, he walked to a nearby barn spotting someone entering. It turns out to be the hiding Jason Voorhees waiting for his next victim. He slits his throat and takes his hockey mask and harpoon. As he bleeds to death, Shelly tries to get help and stumbles his way back to the main lodge at Higgins Haven. Chili encounters him before a blackout was caused by the death of Chuck and sees his fatal wounds but believes he was pulling off another one of his tricks. About to go out and find Chuck, she stumbles over him and he slumps over on the floor finally realizing that Shelly wasn't pulling a prank this time and really is dead.
Shelly was the seventh victim in the film and the fourth victim of The Wild Bunch.
His body was eventually found and taken away.
In the non-canon future in the comics, using power he had acquired from reading the Necronomicon Ex-Mortis dream-based killer Freddy Krueger summons a Deadite version of Shelly (along with Deadite versions of one of Jason's other victims Jimmy and one of Roy Burns victims, Eddie) to attack Jason in the winter of 2009. Swarmed and beaten by Shelly and his fellow demons Jason ultimately gains the upper hand, slaying the ghouls of his victims upon regaining his machete.
- Freddy vs. Jason vs. Ash (2007 - 2008)