Short answer: In the final act, Sue tries to become a permanent, self-sustaining version of herself by misusing the Substance a second time. The result is Monstro Elisasue — a grotesque fusion of Sue and Elisabeth Sparkle — who crashes the New Year’s Eve taping, is beheaded on live television, and collapses outside the studio. What is left of her crawls to Elisabeth Sparkle’s star on the Hollywood Walk of Fame, looks up at the stars one last time, and dissolves. A street cleaner wipes away the remains the next morning.
Spoiler warning: this breakdown covers the entire ending of The Substance (2024), directed by Coralie Fargeat. Read on only if you have seen the film or want it fully spoiled.
Recap: how the ending begins
Elisabeth Sparkle, a fading television aerobics star fired on her 50th birthday, takes the black-market treatment known as The Substance. It generates Sue, a younger, “better” self, from her own body. The one rule: switch consciousness between the two bodies every seven days without fail, and keep each body alive.
Sue breaks the rule. She refuses to switch back for weeks, draining Elisabeth’s stabilizing fluid to fuel her own ascent. When the New Year’s Eve taping of her show approaches, Sue has no fluid left. The Substance supplier tells her there is only one way to get more: switch back into Elisabeth so the fluid can regenerate. When she finally does, she finds Elisabeth in ruins — aged, hunched, deteriorated beyond recognition by Sue’s neglect.
The termination — and why it goes wrong
Elisabeth decides the cycle has to end, and acquires a termination serum meant to kill Sue permanently. Mid-injection, she falters. Part of her still craves the youth, the applause, the second chance Sue represents. Because she only half-commits to the termination, Sue doesn’t die — she reanimates, and for the first time in the film, both selves exist simultaneously in the same room.
Sue, realizing what Elisabeth was trying to do, beats Elisabeth to death in a frenzied rage. This is the point of no return: with the original host body dead, there is nothing left to sustain Sue either. Her body begins to collapse — an ear falls off, teeth loosen — as she prepares for the New Year’s Eve show she has built her entire identity around.
Monstro Elisasue: the final injection
In a panic, Sue does the one thing the instructions forbid — she injects herself with the activator fluid a second time, using her own body instead of Elisabeth’s. The result is Monstro Elisasue: a hunched, pulsating, multi-bodied fusion of Elisabeth and Sue, a creature that is both of them and neither of them.
Monstro puts on a paper mask printed with Elisabeth Sparkle’s face and goes to the studio anyway, determined to have her New Year’s Eve moment. The mask falls off in front of the live audience. The crowd recoils in horror, and chaos erupts. In the frenzy, Monstro is decapitated — and one of the most excessive blood-spray scenes in modern cinema plays out over the screaming audience.
The last scene: the star
What remains of Monstro Elisasue escapes the studio and collapses in the street, a melting mass. From the viscera, Elisabeth Sparkle’s original face emerges one final time. She drags herself to her own star on the Hollywood Walk of Fame, looks up at the night sky, and smiles — before dissolving into the ground. The next morning, a cleaner nonchalantly mops the remains away. Fame, the film seems to say, is disposable.
Competing interpretations
The addiction reading. Many viewers read The Substance as an addiction allegory: the activator works exactly like a drug — euphoric first hit, escalating doses, a supplier who warns you about the rules you will inevitably break. Sue’s refusal to switch back mirrors the addict’s refusal to come down. In this reading, the ending is a straightforward overdose-and-destroy arc.
The self-hatred reading. A second camp argues the film is about internalized self-hatred — Elisabeth literally becomes the abuser she once fought against, tormenting her older self the way the industry tormented her. The fact that Sue and Elisabeth are the same person makes every act of violence self-harm. The ending then reads as the final, fatal consequence of a woman at war with her own aging.
The fame-culture reading. The third, and most widely cited, interpretation is that the film is a satire of an entertainment industry that consumes women and discards them. The New Year’s Eve show is the entire point — Monstro Elisasue drags a dying body to a television stage because being seen matters more than being alive. The final smile at the star suggests the film’s bleakest thesis: that a woman destroyed by fame can still experience one last, hollow moment of it.
FAQ
What is Monstro Elisasue? A monstrous fusion of Elisabeth and Sue created when Sue injects the activator fluid into her own body, breaking the treatment’s cardinal rule. It is the physical embodiment of the two selves forced into one body.
Why doesn’t Elisabeth finish terminating Sue? She hesitates because part of her still wants what Sue represents — youth, relevance, admiration. That half-commitment is the fatal error: it leaves Sue alive and enraged.
Why does Sue kill Elisabeth if it destroys them both? Rage and denial. In the moment, Sue acts out of pure fury at being “betrayed.” She does not think through the consequence — that killing her host body kills her future too — until she starts falling apart.
What does the ending mean? There is no single answer, which is why the ending endures. Read literally, it is the catastrophic failure of a vanity treatment. Read thematically, it is a warning about addiction, self-loathing, or an industry that chews women up — pick the lens that fits, because the film is designed to support all three.