Lori Spengler

Lori Spengler is the main antagonist of the horror-comedy film Happy Death Day.  She was the roommate of the film's protagonist Theresa "Tree" Gelbman, who she desired to kill for having an affair with Lori's love interest, Dr. Gregory Butler.

She was portrayed by Ruby Modine.

History
Lori was a student at Bayfield University, a nurse at the campus hospital and the roommate of Tree Gelbman. Though she always acted nice to Tree, she actually held a deep hatred for her and her snobby obnoxious attitude. However, once Tree started having an affair with her Professor, Dr. Gregory Butler (who Lori had also sought an affair with), her hatred boiled to the point that she wanted to kill Tree and anyone that stood in her way.

She first attempts to kill Tree on her birthday by offering her a cupcake laced with poison. Tree refuses to take the cupcake by throwing it away. Later on that night, Lori dresses up in a black outfit and conceals her identity with a baby mask, which she took from the schools' football team merchandise. She distracts Tree by putting a music box in a tunnel where she walks in and when Tree bends down to get it, she sneaks up behind her and stabs her to death with a hunting knife.

Tree ends up in a time loop and thinks that her death was a dream, but then Lori once again kills her in the next loop by stabbing her again with a broken bong, but only after she kills her fellow sorority sister Danielle's boyfriend Nick by stabbing him to death. In the next loop, Tree complains to Lori that someone is trying to kill her. Lori suggests that Tree conceal herself in her dorm room. Later on that night, Lori breaks out of the bathroom and kills Tree once again by stabbing her to death.

In each of the loops, Tree tries to track down the suspects each of which could be the killer who is targeting her on her birthday. She first suspects Tim, but while he is looking at gay porn, she is killed by being stabbed in the stomach. Next, she suspects Dr. Butler's wife Stephanie, but spots her moments before the killer drowns Tree in a fountain. She next suspects Danielle, but when the two get into a fight, they end up in the path of a bus which runs them both over. In the next loop, Tree suspects someone who is dressed a black hoodie as the killer, but when she bludgeons the figure with a baseball bat, it's revealed to be another sorority sister named Becky. Lori again kills Tree by bludgeoning her with the bat.

Tree's final suspect is Gregory. However, while she is the hospital after passing out, she gets an x-ray which reveals some of the injuries she sustained while being killed in the previous loops. Tree searches through Butler's office to which she finds a baby mask. Then, Lori dressed as the killer appears and kills Butler before chasing Tree. Tree manages to escape, but when she is pulled over by a police officer while driving away, she volunteers to be arrested to avoid the killer. Lori appears and runs over the cop before dropping a birthday candle on the leaked gas of the car which explodes and kills Tree.

Tree in another time loop sees a news report on television about a serial killer named John Tombs and suspects that he's the real killer because he is notorious for going after young women. She decides to go after Tombs at the hospital but while there, Tombs kills a security guard, takes his gun and escapes from his room. Tree attempts to defend herself by using a fire axe, but it's shot out of her hand. Her friend Carter Davis tackles Tombs and disarms him, but he's killed while protecting her. Tree manages to incapacitate Tombs, but realizes that if she stops the loops, Carter will stay dead. She goes up to the bell tower and hangs herself.

Tree in the next loop after resolving to be a better person prepares to go after Tombs. She sets her watch to 30 for thirty minutes so that it would go off during a black out, carefully steals the security guard's gun and tells him to call for backup. She enters Tombs' hospital room and tries to shoot him while he's still asleep, but the safety is on. Tombs gets up and fights Tree by slamming her into the wall. When the blackout occurs, she uses it to escape his line of sight and shoots him to death. Tree then finally eats the cupcake that Lori gave to her after her date with Carter and falls asleep, not knowing that the cupcake was poisoned.

Tree in the final time loop enters her dorm room where Lori greets her with the cupcake again. She tells her that she ate it the night before when she knows that she didn't. She then realizes that she died in her sleep and that the cupcake was poisoned, leading her to realize that Lori is the true killer. Since Lori works as a nurse at the hospital, she used Tombs as a back up and a scapegoat because of his history. Tree tries to coerce Lori to eat the cupcake, but when she refuses, she decides to take it to the police.

As Tree prepares to leave, Lori grabs her hair, slams her against a closet door and locks the bedroom door. She confesses to being the killer and is angry because of the affair between Tree and Butler and that she was upset because Butler preferred Tree instead of her. The two engage in a struggle as Lori tries to finish off Tree for good, but they are interrupted by Danielle who heard the noise from outside of the room.

Lori tries to act like nothing is happening while pinning Tree to the bed, but Tree takes the cupcake and shoves it into Lori's mouth after shouting "Eat It Bitch!!". As Lori struggles rubbing the cupcake out of her mouth, Tree grabs the ceiling lamp and kicks Lori out the window to her death. Lori lands in front of a fellow sorority sister named Emily, who screams in horror and runs away while Tree looks down at her roommate's dead body.

Happy Death Day 2U
After Tree is knocked back into another dimension, she goes to her dorm room to confront Lori about the poisoned cupcake to which Lori tells her that there is no cupcake meaning that she is not the killer in this timeline.

Later while spending time with her now alive mother Julie, she sees a news report about John Tombs, Lori's scapegoat in the previous timeline, being taken into the hospital. She goes there to kill him by grabbing a fire ax to which she is caught by a police officer and arrested. As he escorting her out the Babyface killer appears and kills the cop before pursing Tree. She still thinks it’s Lori until Lori turns up in the elevator behind her and grabs Tree to safety. Lori takes her through an area that’s under construction, but the killer appears and kills Lori by stabbing her in the chest. He then chases Tree up the stairs, but she manages to trip him down. He gets up quickly and catches Tree on the roof. She loses her balance and falls to her death.

After being revived in another time loop, Tree goes to the lab and tells Ryan Phan and his friends Samar Ghosh and Dre Morgan that she has to die multiple times in order to find out who the new killer is and close both time loops so they can fix the reactor. In a suicide montage, she electocutes herself in a bathtub, drinks drain cleaner, dives into a wood chipper, skydives in her bra and panties with no parachute (while flipping the bird and deliberately landing in front of Carter and Danielle), and also jumping to her death. However, when she wakes up again, the added trauma from her constant dying continues to take its toll on her, and she collapses in Carter’s arms before he takes her to the hospital.

While in the hospital she sees Gregory Butler (whom she had an affair with in the orignal timeline) but he doesn't know her as she not one of his students and is instead having the affair with Lori. She tells Butler to get Lori away from Tombs while she is escorting him to the operating room. Tree escapes and knocks the cop out to take his gun. When she gets to the OR, Lori is already dead. Tombs appears behind Tree, but she shoots him twice. She asks who freed him, right before the killer appears and tries to grab the gun out of Tree’s hand. She sees a tank of flammable gas and shoots it to kill them both.

In another time loop, while having a tender moment with her mother, Tree once again sees a news report that Tombs has escaped again and has killed Lori, Carter and the cop. Tree realizes she has to stop the loop from closing, or else Carter and Lori will stay dead. She grabs the car keys and rushes out, trying to reach Ryan but fails as he and the others are gearing up for the reactor to go off. Tree then drives toward an electrical plant and charges into a box just a second before the reactor goes off once again killing herself.

Tree is revived and goes to tell Ryan the algorithm, but this time, she has decided to return to her original timeline. Bronson and two security guards then come in to seize the reactor a whole day earlier than planned. Needing an urgent plan to steal it back, Tree gets Danielle to pose as a blind French student to distract Bronson while they take his keys and get into the office where the reactor is before taking it back to the lab.

Before returning home, Tree goes around trying to get closure. She approaches Lori and sincerely talks to her about ending her affair with Gregory, as she knows it’s not worth it. Tree then gives Lori a hug. She then goes to Danielle’s room to say how wrong she was about her, only to find a guy emerging from the bathroom with nothing but a towel, and Tree sees that Danielle sucks in both dimensions. Finally, Tree goes to have the birthday lunch with her parents, but she asks David to let her have a moment alone with Julie, which is basically Tree having one more final moment with her mother.

Tree goes to the hospital that night to save Lori. She gets to the room with the cop’s gun and kills Tombs before he can attack. The ladies run out but are cornered by the killer. Tree correctly guesses that the killer here is Gregory, wanting to silence Lori for the affair. Before they can run, Gregory’s wife Stephanie (Laura Clifton) shows up to shoot Lori. She hands the gun to Gregory to kill Tree, but he shoots Stephanie first. Tree runs and grabs a weapon, and Gregory goes after her. He gets Tree in a room containing a high-powered magnet that he doesn’t notice…but Tree does. She holds a screwdriver as he draws his gun on her, but she has some final words for him: “You’re screwed.” With that, she turns the magnet on, and Gregory gets caught in it by a metal chair. Tree releases the screwdriver, which runs through Gregory’s chest, killing him.

Carter shows up, and he and Tree help Lori onto a stretcher. Tree tells Lori she is sorry for how things turned out, and how she wishes things could be different, even though Lori doesn’t know what she means. Meanwhile, Ryan, Samar, and Dre have gotten the reactor up and running, but Bronson and the guards are trying to stop them again. Samar and Dre hold them off as long as they can while the reactor turns on. Tree tells Carter again that they are together in the other timeline, and they share a kiss right just as the reactor reaches its mark, a mere second before Bronson can pull the plug.

Everyone returns to the correct timeline in the beginning where Ryan, Samar and Dre were activating the reactor. After Tree asks Carter about Danielle (as he was dating her in one of the time loops) he confusingly asks "who?" Tree becomes happy that Carter remembers her now and pounces on him to make out with him before the film ends. It could be assumed that in this timeline that Lori's fate is unknown as she wasn't seen in the mid credits scene.

Victims

 * Tree Gelbman - Multiple different murders.
 * Nick Sims - Stabbed to death.
 * Gregory Butler - Stabbed.
 * Officer - Ran over.

Trivia

 * She technically never kills anyone, as all of her previous murders are undone each morning when Tree wakes up, though the mental damage of them lasts for a while.
 * According to the film's director, Christopher Landon, an unused draft had Lori and Dr. Butler as lovers conspiring to kill Tree.
 * The alternate ending (the film's original one) had Tree hospitalized after her ordeal with Lori, only to be murdered permanently by Dr. Butler's wife.
 * It seems like she will be ressurected in the sequel through the time loops, but not as the killer.