Partial Players are fake players created by real players: regular people, volunteers of the experiment. They usually stop in one single place. The names, clothes and items in hand are all randomized. They drop skin and organs at death.
The Zombie is a highly hostile creature rising back from the dead and spreading its infection. It is slow and has a low resistance, but it can quickly create a whole army if someone isn't cautious enough. It drops organic gump at death.
Bugs are gigantic green insects which like to have protection, usually wearing things on their torso and head, as those are strangely their weakest parts. They are weak in general, but 'clothes' help them. They drop string at death. If they're wearing something, they'll drop that.
The Robots come in different variants, being friendly, neutral, aggressive, or broken. Broken Robots can be repaired with robot parts, obtained in containers or by killing other Robots. They then turn into Robot Servants, who protect and obey the maker. They drop robot parts at death. The Robot Servant, instead of dying, when killed it becomes a Broken Robot.
SPOILER ALERT - IF YOU WANT TO FIGURE THIS OUT YOURSELF DON'T HIGHLIGHT THIS TEXT
Ectoplasm can be used on a Broken Robot to create a Possessed Robot.
It's a flying robot that's pretty strong. It is obtained by (look at the spoiler up here). It drops ghost metal at death.
NOT TO BE CONFUSED WITH MANNEQUIN
The Manneking resembles a normal mannequin, like any other, but trembling, with white eyes. When someone looks at it, it immediately disappears and damages the looker by 2 health. It cannot be hit or killed.
Both the Magno and Magner are human-sized magnets with legs, with the Magner being bigger. The Magno's primary color is red, the Magner's primary color is blue. The Magno is a 'pull' magnet that follows people holding metal items, while the Magner is a 'push' magnet that kills them. The Magner has 12 health, the Magno has 8.
The Ghost is a passive invisible entity, appearing as a floating eye. It has a 1 in 50 (variable) chance of spawning when waking up. It is friendly, and keeps being friendly, until a nearby person steps. At that point, the Ghost enters an aggressive state. However, triggering it can be avoided, as it disappears 20 seconds after spawning. It drops ectoplasm at death, but not when disappearing.
Blind Voltage is a semi-aggressive entity which, unlike most entities, does not possess an official document. Instead, a sign written by Matt, one of the four janitors, can be found in the rooms it spawns in, explaining its main characteristics. Like the sign says, it's a yellow creature that can't see but can hear and sense your movement through... electricity?
The Meatball is an aggressive entity appearing as a floating meatball, it causes an explosion when hurt or touched in general. For this reason, it is immune to explosions. It is advised to keep distance while fighting the Meatball. It drops meat at death.
The Tesla Slime is a slimy 'aggressive' entity that inflicts any person stepping in a 3 block radius with the Conductive effect for 30 seconds. It is advised to crouch when going near it or, if trying to fight it, keep distance.
Heliofused is a flat entity which resembles a drawing of a green sun with a face and closed eyes. This entity constantly lights up and gives anyone touching it the Sun Sickness, a disease which causes its host to be hurt while being in dark areas.
The Shadow Ruby is a highly aggressive fast flying entity with a gem-like shape. It's totally black and can kill anything in one shot. After this is done, it disappears.
mag.net is a boss that always spawns in the server room at room 50. It occasionally spawns minions: Magnos, Magners and Serverbugs. It has 350 health and drops a mag.net card which can be used to escape the room.