Specimen 7 resembles a large, moving, red and black wall of distorted corpses.
Upon entering the door, the player sees themselves in a blood red, rotating hallway. After exiting this hallway, Specimen 7 will start chasing the player. From that point on, the player must run through a series of twisted maze-like corridors with shifting images along the walls, created by the player's mind under the influence of Specimen 7. The chase sequence will end at Room 430.
Though slow, Specimen 7 kills the player immediately upon contact.
The best method of avoiding Specimen 7 is to focus only on finding the path to the exit, and not succumb to the environmental distractions.
Specimen 7 is the only specimen in the game to span the entire horizontal length of each room it chases you in. Due to its form as a shifting wall, Specimen 7 will slowly consume the entire room from its direction, killing the player on contact. Therefore, it is essential to reach the exit as quick as possible.
The labyrinth Specimen 7 chases you in branches into various dead ends, meaning the player must be alert of their surroundings and quickly backtrack when necessary.
The shifting images that appear on the walls are only meant to distract the player, but have little impact on navigation - they do not attack the player by any means. The player should then simply ignore them, and focus on escaping.
"STRANGE WIGGLES", Specimen 7's chase theme.
- The White Cat's relation to Specimen 7 is unknown; for some time, the cat was suspected to be Specimen 7 itself, and may indeed be a part or a consequence of its existence.
- Since The White Cat references archetypes from Jungian Psychology, the cat's role might be akin to a therapist, with Specimen 7 being the trauma being treated. Considering the last piece of advice The White Cat gives the player is "Knowing your shadow can greatly help you, but be ready to see what you'd rather not be", it's possible that Specimen 7 is a manifestation of The Protagonist's shadow archetype, or is related to it.
- Specimen 7 is visually similar to Giygas's final form from Earthbound (or Mother 2). The otherworldly atmosphere and presentation of Room 410 may also be inspired by Earthbound or other similar games.
- It could've also been inspired by the Living Wall from Dungeons and Dragons.
- It is also similar to the deathmatch intermission screen seen in Doom.
- In the 2.5 update, the player no longer stays in Room 410 for the duration of the chase: it now progresses.
- Specimen 7 lacks a death screen, along with the old version of Specimen 10 and the old version of Specimen 3.
- Specimen 7 can be encountered one time only, along with Specimen 13.
- It is one of three specimens that can instantly kill the player on contact, the others being Specimen 9 (in the HD Renovation) and Specimen 12 (while in Room 810).
- The art for Specimen 7 is recycled from another project Akuma Kira was working on.
- Specimen 7, along with Specimen 13, are the only two specimens from the original game to be absent in Endless Mode.
Unlike the original game, the Specimen is now 10 degrees at an angle and the rooms the chase take place in are now slightly darker.
Specimen 7's starting room has been drastically changed. Now, the player will see a hallway with the threshold of consciousness sign on the floor. The player will have to run into the wall, breaking it down. Then, a massive room is seen with a huge clock in the middle of it.
On each side is all the doors for the other rooms. The player must enter a door which leads to the normal room layouts for a few rooms. In these few rooms, other specimens may give chase, albeit for a very short time.
Specimen 7 moves a lot slower now.In Endless Mode, Specimen 7 can now appear like in Story Mode within its rooms and will not re-chase, like Specimen 13. No other specimens can join the chase, although specimens can chase the player when going through the rooms around the clock.