Parasite (NOTD)

Parasites are small and easily missed. They blend in well with terrain and move deceptively fast. Parasites are frequently found in the stomachs of large enemies such as Agrons and Infestors and will emerge if the creature dies.

Parasites stack venom at an alarming rate when they attack. Any player caught with their shields down will suffer heavily if attacked by these tiny creatures. Their attack is very weak, but fast, and can easily go unnoticed.

Parasites erupt from Tartarus upon his death and appear patrolling the map during the Nydus Worms Mission. They also spawn from Eos the Zombie Queen when she is killed in Easy Company. On high Squad Rating games, Infestors will erupt both creep and parasites when killed. This combination can be deadly to any players lingering too close.

Lastly, on Nightmare, Parasites can charge brief distances. Because of this, be very wary when killing large enemies on or around creep. The combination of speed buffs can allow Parasites to quickly attack and stack a lethal amount of venom.

Note that the parasites that spawn on wave 16 of Survival mode do have the ability to detect cloaked marines.