The spawn cylinder is a metal pod like object that has metal on the outside and pieces of metal sticking out on top. A glass door covers the inside of the cylinder. Inside the cylinder is a glass pod like object, that is a proto-suit, being held up inside the cylinder.
At the start of each level in Test Subject Blue, the scientist's hand, holding a big syringe, will put the syringe on top of a cylinder, and press the top button, which will insert a blue enzyme into the proto-suit. The pod like object will drop to the ground, where the suit's legs will go down, stopping the pod from smashing against the floor.
The metal arm parts of the suit will come out of the back, the glass door will open on the spawn cylinder, and the player will be able to control Blue. Every time Blue dies, the spawn process will start over again, except the scientist's hand and the syringe will not come out. The cylinder has a special thing inside it for holding the blue enzyme liquid, the liquid which will also go into Blue's proton cannon.
Sometimes in levels of Test Subject Blue, a second spawn cylinders may be placed in the level. The second spawn cylinder in the levels of Test Subject Blue appear as a usual spawn cylinder, except the proto-suit pod is not inside it. When the second cylinder is touched, a pod will appear and Blue will spawn from their when he dies. Second spawn cylinders are usually placed in levels to make them easier and reduce walking for Blue.
If the player quits the level, and enters it again, they will be spawned from the first spawn cylinder, and not the one they previously touched.
Spawn cylinders appear in Test Subject Arena, but have a different appearance: they have a holder for the player's goo. In Test Subject Arena, the objective of each level is to deplete the opposing player of their goo. In each level, each player starts with half of their goo holder full. The player obtains goo by killing the opponent, the same goes for the other player. The player will also obtain goo if the opposing player is killed by hazards, same for the other player.
The player's goo will increase the more the opposing player dies. When either character dies, they have to use some of their goo to respawn out of their spawn cylinder. The goo holding spawn cylinders were made for Test Subject Arena and appear in all levels of arena. Goo-holding spawn cylinders will probably not appear in any other Test Subject game.
- Main article: Spawn areas