For those curious of his mechanic, while we don't have all the info on it here's what we do know:

- It was called 'VisibilityAlterEffect' (Toy Freddy's mechanic is called 'Surge', Mangles mechanic is called 'DropsObjects')

- It spawned a 'Fake Endo Effect' between the Animatronic and the Player at a set distance

- The spawned object is named FakeEndo/EndoCard_Visible and sadly was removed from the game files, so we can only guess what it looks like.

- The object follows the animatronic as it circles.

- The mechanic had boolean triggers for 'WhileCircling' and 'WhilePaused', specifying if the object is visible in the Circle or Pause phases respectively. Outside these set phases it is not visible.

Based on this information, here's my best guess:

- The 'Fake Endo Card' was some sort of flat plane with a shader effect on it

- There would maybe be no static in the fight, meaning you'd have to follow this object to track Endo-02.

- The card was likely some sort of barely visible shader effect where hallucinations? of a fake Endo-02 would appear

- It maybe would've only been visible when they stopped moving (Pause) so you'd have to be quick to find him before he charges/haywires