Wallter is an NPC that can be found in-game, and will enter the elevator. Wallter has the appearance of a tall, grey humanoid figure with a beige torso, dark gray legs, and a spherical head with a drawn-on smile. Unlike most other NPCs, Wallter has more than 6 body parts, as he has 10 extra joints, implying he has the R15 rig. Wallter is a construction worker that mainly builds with concrete and bricks, and is particularly obsessed with drinking Wet Cement. Wallter is well-meaning, polite, and extremely formal in his speech. His obsession with concrete forms a rift between him and Mannequin_Mark, who prefers wood as a building material and heavily dislikes concrete. As seen in his dialogue, he refuses to believe that Wet Cement is in any way harmful, and tends to insist that others try it out. Wallter seems to like cats, though he doesn't like being gifted Kitty, as seen by his interactions with Gnarpy. 

In Flatgrass, Wallter falls from the arch building and then proceeds to move towards the elevator, entering it if MR is not inside or if the elevator is not full. Wallter can exit the elevator on the Hole in the Wall floor or on the Backrooms floor.

On the Hole in the Wall floor, Wallter will fit into the titular hole in the wall. From there, he will either seal the hole or slide through the hole and run away. On the Backrooms floor, Wallter exits the elevator and walks aimlessly. On the Intense Obby floor, Wallter will exit and do the obby as if they're a player, though players can beat him to the end.

- I see wallter as a laid-back guy, who  just goes with the flow. he is polite, formal, and well meaning. Do what you will with this!