Endo01

Endo01 (GLITCH in files) is a hidden character in Five Lost Nights.

Appearence
Hence the name, he appears to be a glitched endoskeleton.

Appearences
If you hold the keys E, N, D and O while the cursor is on the Scrap Room endoskeleton, he would appear on your screen for a few seconds and the text "HE KNOWS" would appear. The endo is gone after.

On Night 2, holding the keys K, N, O and W on the NOW HIRING poster outside the place will make Endo01 appear again, with the text "BUT WE KNOW HIM" appearing. The poster will be a Freddy poster instead.

On Night 3, honking the (rare) Fredbear plush nose 5 times will bring Endo01 up and the text "WE WERE FORGOTTEN TOO."

On Night 4, when the Bathroom cam shows, putting the cursor over the shadowy figure for 10 seconds. This should bring Endo01 up and the text "LEFT BEHIND FOREVER".

On Night 5, Endo01 will show up on nearly any poster in the Party Room cams. Clicking on the poster will bring up the text "YOU WILL NEVER LEAVE, YOU WILL JOIN HIM."

FORG?TTEN Ending
This ending occurs once Endo01 is brought up in all nights. The pizzeria has closed down, and the player walks around the place while getting stalked by Freddy. When the player approaches the backroom, they will get locked in, and the text "THE END OF THE GAME" will appear, followed by Endo01's image. The screen fades to the FORG?TTEN Ending screen, with the cast looking at you. The ENDO_STAR will be earned.

Five Lost Nights 2
Endo01 does not appear due to being 'forgotten' according to the Phone Man. Endo02 takes his place.

Five Lost Nights 3
In the Night 2 cutscene, Endo01's image returns and the text "DO YOU REMEMBER ME FROM THE FIRST GAME?" He then disappears while glowing pupils look at you in the background. The text "WERE YOU HIM?" then appears.

Trivia

 * Endo01 appears to be breaking the fourth wall.
 * Endo01 could be the cause of the forgotten memories in the series, claimed to have made everyone forget stuff (according to the Phone Man from FLN2)