Undyne, devastated by Alphys's death, has transformed into Undyne the Undying, the Genocide Boss Battle from canon; due to her living on the surface and incorporating physical matter into her form, it's more stable in the episode than in the game. Nothing Betty tries works- Undyne easily pierces Kumu's shield because of her determination, the spears just come from everywhere so she can't dodge, and even Rhabdophobia is ineffective as Undyne can easily replace her lost spears- and then some. When Undyne demolishes Betty with a special attack called Spear of Justice, Kumu tries to save her by consuming the vial of Hate left over from Chara's purification. This allows her to heal and get back up again, but with the unwelcome side effect of making her Hate's puppet.
Even with Hate, all Betty can manage to do is recover her mind to some extent and escape from Undyne. Back in her hiding place, Betty berates Kumu for consuming the vial, before immediately apologizing and admitting how terrified she is of the Hate that's corrupting her and trying to turn her away from her mission. In the meantime, though, she has an Evil Plan to execute.
Back with the heroes, Jessica warns everyone in the city about Betty's plan, though there's still friction with Gaster, who hasn't forgiven her for helping Betty. Undyne returns and is comforted by Papyrus, and Frisk gives Jessica the Integrity Soul's ballet shoes and tutu, the weapon and armor set you can find in Undertale. Frisk then meets Asriel outside and explains a few things.
One, the current timeline is in Hard Mode. When Frisk did the True Reset after Megalomaniac, they put their own name on the save file, despite the warning that it would "make [their] life hell", in hopes of getting something better than the canon Golden Ending. The original idea was that if things got too hot for them, they'd just reset- which they tried to do in Darker Yet Darker, but Gaster stopped them. Two, they'd been trying to reset since the very start of Season 2, and this was the real reason Sans got so mad at them in Dust. This is because they had thought they would cease to exist when they broke the reset button, and thought that the pacifist ending would continue on the surface without them- when that didn't happen, and Frisk continued with everyone else, they became sure something bad would happen. But now Frisk's lost control on the timeline, and blames themselves for Betty appearing and wreaking havoc.
Asriel tries to comfort Frisk, but they rebuff him, and gain LV in the process; in this series, even hurting people in nonphysical ways can raise LV. Frisk has hit the Despair Event Horizon, and does not believe it is possible to defeat Betty without LV.
See you in Love, Pt. 2.
Tropes
- Curb-Stomp Battle: Betty stands no chance against Undyne the Undying. Even Hate's upgrade isn't enough to allow her to win, just to escape.
- Despair Event Horizon: This marks the point where Frisk is in despair about being able to defeat Betty, even more so than in previous installments. It also marks an upswing of cruelty in their behavior to get stronger.
- Super Mode: Undyne the Undying is now this to Undyne, instead of a Deadly Upgrade like in canon.
