Orange enzymes are enemies, and one of the three types of enzymes, in the Test Subject series. They also appear as one of eight playable characters in Test Subject Arena 2.


The orange enzymes are piles of orange goop, and are very similar to Blue, only a different colour. Orange enzymes can take on many different shapes and forms, and do so throughout the game.

Game information


Orange enzymes, along with pretty much everything in Test Subject Blue, was made by the scientist. The orange enzymes went also through the same tests Blue endured, although the orange enzymes were not trying to complete the puzzles.

In the ending of Test Subject Blue, an orange enzyme was combined with a blue enzyme, to create a green enzyme, who came out confused.

The orange enzymes, along with all other enzymes the scientist made were taken to another lab after Doctor Nastidous destroyed Xeno Industries.


There are four different types of orange enzymes encountered in Test Subject Blue, with possibly more not shown in the game. Different types of orange enzymes have different types of abilities. Four types of orange enzymes - walking, shield, dodge, and flying - are the only enemies in Test Subject Blue.

All the orange enzymes appear in Test Subject Green, but are used one to two times throughout the game, as green enzymes are used more often. The orange enzymes, along with all other enzymes the scientist made were taken to another lab after Doctor Nastidous destroyed Xeno Industries.


Main article: Walking orange enzymes

Walking orange enzymes are the first type of enzyme introduced. They are spawned from a mine-like object and will walk straightforward, not turning. They can be killed with one blue proton bullet.


Main article: Shield orange enzymes

Shield orange enzymes walk horizontally holding a shield in front of their face which will protect them from attack. When Blue approaches one, it will instantly face its shield to face the main character. One bullet to the back will kill the enemy.


Main article: Dodge orange enzymes

Dodge orange enzymes will stay in one place, but will adjust their body to avoid Blue's proton bullets. They are low at coming back up, which is their only weakness. Timing is needed to kill them. One bullet will kill them.


Main article: Flying orange enzymes

Flying orange enzyme's are immune to Blue's proton bullets. To kill one, its own bullet must strike itself. To do this, the player has to fire a proton bullet at the flying orange enzyme, who will fire it back at Blue at a faster speed. This bullet, if it goes into them, will damage them. Two bullets will kill them.


Main article: Orange enzyme bullets

Orange enzyme bullets are circular orange bullets. They are actually orange enzymes in bullet form. They are fired from guns in walls and detection proton cannons. These enzymes cannot be killed as they instantly die when they touch a wall, and will instantly kill Blue if contact.


Main article: Throwing orange enzymes

Throwing orange enzymes are hunchbacked orange enzymes from Test Subject Complete. When Blue gets close enough to them they will take the lumps that are their hunchbacks and throw them at Blue, usually when Blue fires at them.


Main article: Juggernaut orange enzymes

Juggernaut orange enzymes are huge orange enzymes with huge armor covering their bodies. When Blue steps on the same platform as them they will turn around and head straight towards Blue, so that Blue cannot fire at them from behind. If Blue wants to kill them Blue must fire at them and keep firing. As their armor starts to come off, Blue must keep firing until it is all gone, then eliminate them.


Main article: Cooked orange enzymes


Main article: Dropped orange enzymes


Main article: Enzymes (Bump Battle Royale)

These enzymes appear only in Bump Battle Royale, and come in either orange or green. They die upon contact, but push the player back.

Test Subject Arena 2

In Test Subject Arena 2, the orange enzyme appears as one of the eight playable characters. It appears as a regular walking orange enzyme, although in this game the enzyme is faster. As an attack, it throws a gooey spherical orange projectile, similar to the ones thrown by throwing orange enzymes. This attack is unique to others in that it is thrown at an angle and will also roll along platforms until it hits an opponent or a wall.

When idling (a result of the player not touching any of the controls for a while) the orange enzyme will put on a pair of glasses and scratch his head. A thought bubble will appear with the equation E=MC2 written backwards inside. After doing this, the thought bubble will disappear and the enzyme will take off the glasses.

When the orange enzyme finishes its test, it says "Go home and be a family man.".



  • The mimic green enzymes have the ability to copy the movements and appearance of orange enzymes and blue enzymes, only they appear green when mimicked.
  • Orange enzymes were presumably going to be the main characters of Test Subject Blue before it was changed to blue enzymes. This is seen from concept art of the proto-suits.
  • The orange goo from the Swindler series was probably inspired by the orange enzyme, as they are very similar in appearance.
  • The orange enzyme has differing amounts of fingers in its different appearances. In-game, it has three fingers on each hand, in its Test Subject Arena 2 challenge complete sprite, it has five fingers on each hand, and in all other appearances it has four fingers on each hand.