Warning: SPOILERS Below for Happy Death Day 2U:
Happy Death Day 2U ends with a post-credits scene that sets up Happy Death Day 3. The stinger also opens up the world of Happy Death Day beyond the college campus of Bayfield University and hints at the greater ramifications of the technology that caused the time loops that trapped Tree Gelbman (Jessica Rothe).
The big revelation in Happy Death Day 2U was that Tree's time loops were caused by a device invented by Ryan (Phi Vu), the geeky roommate of her boyfriend Carter (Israel Broussard). Ryan and his lab partners Samar (Suraj Sharma) and Dre (Sarah Yarkin) built a machine called the Sisyphus Quantum Cooling Reactor (SISSY for short), which they hoped would prove time could be slowed down. Instead, SISSY malfunctioned and caused Tree to get caught in a time loop in Happy Death Day. When Tree finally freed herself, the loop ended up being passed to Ryan, who found himself the victim of his own Babyface Killer. Happy Death Day 2U gets even weirder, with Tree ending up not just in a new time loop but also trapped in a parallel dimension - which she prefered for a while since it mostly seemed like a better version of her life.
After spending weeks in the parallel dimension's time loop forced to continually relive her birthday, Monday, September 18th, Tree ultimately decided she had to return to her universe. She learned the necessary Quantum Mechanics to get SISSY to properly close the loop and jump her back to her proper dimension (after Tree unmasked and stopped the mirror dimension's new Babyface Killer). SISSY worked as intended and Tree was back where she belonged - and it was Tuesday, September 19th. But here's how Tree's happy ending got a new winkle in the post-credits scene that sets up Happy Death Day 3:
- This Page: What Happens In Happy Death Day 2U's Post-Credits Scene Involving DARPA?
- Page 2: What Danielle's Time Loop Means For Happy Death Day 3
What Happens In Happy Death Day 2U's Post-Credits Scene
Happy Death Day 2U's mid-credits stinger shows that Tree really is free of her time loops at last. After she, Carter, Samar, Dre, Ryan, Dean Bronson (Steve Zissis), and the security guards woke up in the lab (with Tree once more back in her own dimension where Carter is her boyfriend), the group finds themselves doing community service picking up trash, no doubt as punishment for defying the Dean and causing SISSY's reactor explosion. As Ryan tries to explain to Dre how SISSY acted like a slingshot that pulled Tree back to her proper dimension and closed the time loop (and Samar ate a churro he found on the ground), a fleet of black SUVs arrived.
Agents of DARPA (Defense Advanced Research Projects Agency) led by Dr. Isaac Parker (Kenneth Israel) approached the college students and asked them to come with him. The group is brought to a DARPA laboratory where Dr. Parker reveals that he has "borrowed" SISSY and brought it to the lab (no doubt Dean Bronson was happy to be rid of it). Dr. Parker goes on to praise Ryan, Samar, and Dre for creating SISSY but noted his scientists don't have the right algorithms to get it working - something Tree suggests she can help them with since she spent weeks in her time loop learning Quantum Mechanics and eliminating all of the variables to find the right equation.
Tree also suggests a new test subject to be trapped in a new time loop: Danielle (Rachel Matthews), who the scenes cuts to as she wakes up in her bedroom screaming - obviously, she's now trapped in her own time loop, amusingly setting up the new victim of Happy Death Day 3.
What Does DARPA Want With SISSY?
The invention of SISSY is an incredible breakthrough with huge ramifications, especially for a group of bungling college students, and it's understandable the U.S. Government wants to control the technology. The quantum reactor was intended to slow down time but instead, it has the power to trap a person in a time loop (albeit with bizarre horror movie-like rules where the day only resets if the person is killed). The applications of what SISSY can do have all kinds of possibilities - including being weaponized against enemies of the state.
Happy Death Day 2U's post-credits scene doesn't give much more than an inkling of what DARPA ultimately wants to use the technology for, but considering the experiment they want to conduct involves trapping someone in a new time loop, it's not a hard leap to make that there's an insidious plan for this tech unknown to Tree and her friends. And, despite the dozens of times she has been forced to die either by being murdered or commiting gruesome suicide, Tree didn't hesitate "volunteering" Danielle to be trapped in a time. Tree's not thinking about the dangerous big picture of SISSY falling into the wrong hands (and DARPA might already be the wrong hands); instead, she just wants some revenge on her frenemy.
- Happy Death Day 2U (2019) release date: Feb 14, 2019