Prototype is a NPC that can be found in-game and will enter the elevator. 

Prototype is a doll-like robot with white casing and a floating head adorned with four crystalline horns. The larger, bicuspid red and yellow horns protrude from the top of his head, while the smaller blue and purple horns point out from the bottom. His dark blue eyes have hot pink highlights, and his default expression is neutral with a slightly open mouth. The back of the head is missing its casing, revealing four exposed wires which are in matching colors to the horns. The face plate is fully removable, revealing a different face underneath, which is gray, with circular 'eyebrows', the same color eyes as his faceplate, but this time looking up, two lines for a 'nose', and a grimaced mouth showing sharp teeth.

The torso is all white, and the arms have four claws each, matching the colours of his horns (thumb being red, index being yellow, middle being blue, pinky being purple). The left arm is mostly missing its casing, exposing grey metal plates underneath. The legs are identical and have grey sock-like metal plating on the bottom half, with visible bolts on the exposed metal areas.  

Personality-wise, Prototype is a curious and happy character, with them rarely displaying negative emotions in their dialogue. This curiosity can occasionally be detrimental, as seen when they recklessly smash open crates possibly full of Knived Voombas or Glowing Red Teddies. They can occasionally be extremely logical, something that is not always appreciated, as seen in interactions with Bive and Mozelle. They often study and record information about the other characters, usually without their consent. Their speech is occasionally interrupted by errors and glitches due to their somewhat unfinished and aged state.

Prototype spawns in the Find The Path floor sitting on a power box at the end of the level. When activated at the end, Prototype walks over the full path revealing which tiles should be walked on. He then enters the elevator saying "Ohh!" and "What's this?".

If MR is present in the elevator, or if the elevator is full, Prototype will walk to the end of the path, move to the side of the elevator and fall down the map, making the metal pipe falling noise after hitting the ground, similar to the first falling elevator in the Elevator Shaft floor. However, he doesn't die and he infinitely walks in a straight line until the floor ends. If the floor ends when he's walking on the path, he will not enter the elevator. It's also possible for him to accidentally fall into the abyss while going from a path tile to the platform that the elevator is on.

He exits the elevator on the Cardboard Mansion, Slide 4 Admin, and Two Stud Camp floors, before sitting on the logs in Two Stud Camp, Prototype will throw anything he is holding into the campfire, including Scag.

If the elevator enters the Floppy Shoppy floor, he will exit the elevator but only to pick up Scag, allowing her to enter the elevator with him as well. He will also leave the elevator to pick up crates from certain floors and the trash can from the Reddy's Underground Diner floor.

He responds negatively to being hit but will not attack players that do so. Even though he states otherwise, snowballs cannot damage him and neither can other projectiles.

I see him alot like just a happy sounding robot, sort of with a kiddie-like voice, so do something like that! (also a robot somewhat so, do what you will ;) )

https://regretevator.fandom.com/wiki/Prototype  - WIKI!!!!!!!!!!!!!