Unknown Specimen 2 (A.K.A. Otto the Otter) is an enemy that can be encountered in Endless Mode.


Unknown Specimen 2 is a brown animatronic otter with a perpetually open mouth.


Unknown Specimen 2 lacks a chase theme, the only indication of his presence being his deep belly laugh. It enters the room quickly but slows down to a crawl immediately after. It attacks fairly quickly (0.40 seconds of cooldown) but deals about 15 damage on contact.

If the player's health bar is depleted by the specimen, they are met with a jump scare where his face fills the screen and shakes violently.


Unknown Specimen 2's laughs:

Otter Laugh 1
Otter Laugh 2
Otter Laugh 3

Unknown Specimen 2's death screen sound:

Otto Screech


  • Otto the Otter is based on the animatronics from the horror game Five Nights at Freddy's, namely Freddy Fazbear, who has a similar laugh.
  • It was created due to fans constantly asking Akuma Kira to make a Five Nights at Freddy's inspired specimen. He then proceeded to create Unknown Specimen 2 as a joke enemy.



Otto's mouth tends to slightly close and then open back up, as part of his animation. It now has a full 3D model, along with a proper walking animation, as opposed to the waddling motions of his original sprite. It also has a slight white glow around him, his eyes give off a white light and track the player.


Otto now moves at the same speed as Specimen 2 and its attack cooldown is 3 seconds instead of 0.40 seconds.

It now has his own starting room, which is a pizzeria dining room, with Otto standing on a scene nearby. Otto will be motionless at first, not damaging the player and lacking a collision box. A slice of pizza will be laying on the ground near him, with the option to "CONSUME" it. Consuming it will show the message "Delicious" and activate Otto, who will play a small jingle.


  • Unknown Specimen 2 is the only Specimen in Endless Mode that won't play its "chase theme" (which is completely silent) when first encountered in its starting room, except for Monster 3, who completely lacks a chase theme, to begin with. The ambient track that plays normally in the mansion will instead keep playing, even as Otto activates.
  • Otto's eyes can be seen even when the specimen is out of the player's view, similar to how torches work.

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