A large fracture forms on the right side of his skull, extending down to his eye, and the blood from his mouth vanishes.
The story of Last Breath takes place after thirty consecutive Genocide runs by the player. In the 31st run, Frisk discovers a mysterious door in Waterfall, leading to an encounter with , the "strange figure". Gaster informs Sans of the human's repetitive massacres, granting him the memories of previous resets and agitating him into a state of relentless vengeance.
Phase 3 is widely regarded as one of the most technical and skill-based challenges in Undertale fan content: Sans/Undertale Last Breath Undertale Last Breath An Enigmatic Encounter (Phase 3)
By Phase 3, Sans has been struck down multiple times but refuses to die. As he collapses in Phase 2, Gaster intervenes directly, using Sans as a vessel or "tool" for his experiment on the human. This transformation turns Sans into a manic, disfigured version of himself, often referred to by the community as . 2. Visual and Symbolic Transformation
His facial expression morphs to mimic Gaster’s, featuring a wide, "creepy" smile that occasionally switches to a toothless, open-mouthed grin. A large fracture forms on the right side
Sans’s eyes flicker with static-like fuzz, and his head shakes rapidly, conveying a sense of instability as Gaster takes partial or full control.
The Weight of a Final Stand: An Analysis of Undertale Last Breath — Phase 3: An Enigmatic Encounter Gaster informs Sans of the human's repetitive massacres,
The transition to Phase 3 is marked by a dramatic shift in Sans's physical and psychological state: