This mode is a reference to /x/-tan, a personified mascot of 4chan's /x/ (Supernatural) Board. Press X to activate this mode. It cannot be deactivated until the game is reset or until the day ends. Yandere-chan will change into rainbow leggings, black hair in the form of Midori Gurin's first hairstyle, an eyepatch on her left eye, black underwear, and a black tank top with a heart skull on it. A suspenseful song, "The House of Leaves", will play the entire time.
If the player presses the Left Control button, Yandere-chan's hair will change into the Hateful Mode hairstyle and the eyepatch will be removed, revealing a glowing red eye. The player can press the Left Control button again to return to her former look.
- If the player takes off the gloves that they are wearing, then Yandere-chan will wear the normal school uniform.
- The game's warning referred to this mode, saying that this game contained "true nightmares". This warning was later removed because YandereDev said that it was "cringey".
- This mode was made because of a suggestion on Reddit. YandereDev would only add it if someone made a skin for her, and then she was implemented.
- This mode was implemented in the June 17th, 2015 Build.
- X Mode shares the same music with the Slender Mode.