Corruption

The Corruption is a key factor in SeptiScape, being the cause of many of the egos acting strangely. It was started when the Negative Anti soul reacted poorly to a sample of serum, causing the serum to enhance his negativity in a soul instead of the positive. Feelings such as anger, hatred, and fear can speed up the process of corruption, and the only cure is pure positivity.

Symptoms

 * Amplified mental illnesses and negativity: The corrupted serum causes any negative emotions and mental illnesses to overtake anything positive in their mind. Also causes extreme paranoia.
 * Hallucinations: Most of the victims experienced vivid hallucinations that only serve to worsen their condition.
 * Physical changes: Dark ooze falls from their eyes at a certain stage, while in others their eyes simply glow green. Their outfits may be affected, such as broken glasses and torn shirts.
 * Changes to the Ego's section of the world: Each area of the world reflects the mental state and emotional state of the ego. The corruption can cause subtle or very obvious differences in the environment depending on what stage the corruption has reached.

List of Victims and Effect

 * Robbie the Zombie: Amplified hunger, disorientation and confusion. No known hallucinations. Physical effects were his eyes turning black.
 * Henrik Schneeplestein: Amplified his guilt towards his wife passing away during childbirth and caused hallucinations of her chastising him. Physical effects were broken glasses, dark ooze from his eyes, and bloodstains on his jacket (symbolic of blood on his hands.) The hospital became dark and bloody.
 * Jackieboy Man: Amplified their insecurity and caused hallucinations of citizens mocking him for being weak and powerless. Physical effects were glowing green eyes. His hideout and the surrounding sewers began forming a maze of goop creatures who took on the same phrases he heard in the hallucinations.
 * Marvin the Magnificent: Amplified his imposter syndrome and caused hallucinations of his friends turning on him. Physical effects were glowing green eyes and a slight aura around him. The forest near his carnival warped and created a false tent full of liars and backstabbers.
 * Chase Brody: Amplified his self-hatred, depression, and brought up traumic memories of what Stacy had made him believe about their relationship and why it failed. No known hallucinations. Physical effects were dark ooze from his eyes, a physically impossible bend in the neck, and a red mark on his forehead. The Overnightwatch building was the only affected place, turning into a maze of rooms that didn't connect the way they should, mirroring his confusion on what was real in his life.
 * Sean McLoughlin: Amplified his anger towards Angus, which only made it worse. No known corruption-exclusive hallucinations or physical symptoms. Caused the full mindscape to lose color, including the egos. Exclusive to the Bad Ending.
 * Angus Irwin/AntiSepticEye: Increased paranoia, anxiety and anger. Caused memories of being Angus to resurface. Caused violent lash outs and poor and manipulative treatment of other egos. No known hallucinations and physical symptoms. Anti's corruption caused every ego to become corrupted.

Trivia

 * BingSepticEye and Jameson Jackson are the only egos who were not corrupted at any point in the game. The former due to his relationship with Anti, and the latter for unknown reasons.