- "Warning. There has been a breach in the Experimental Genetic Lab."
- — An-G announcing a Host round
Hosts can be easily distinguished from other zombies by a more deformed appearance; they have a cluster of boils on the left side of their head, covering their left eye. Their right eye gives off a green glow, and their bodies emit green Manticore clouds. The only clothing consists of orange pants. Hosts also have several needles in their torso and arms, signifying that the zombie was being tested on by Atlas scientists.
Hosts appear during special rounds along with a few other zombies. When hitting a player, they become "infected", and must use the Decontamination Zone within 60 seconds or they will die. The player(s) screen will start to darken when the infected timer has reached five seconds and will slowly turn into a zombie. While infected, any hit from a Host will subtract five seconds from the timer while any other zombie will subtract three seconds from the timer. Even if the player is cured by the Zone, they can still be re-infected by the Hosts.
Once the last zombie of the Hosts round is killed, it will drop a Full Reload power-up, and any infected player will be instantly cured without needing to go to the Decontamination Zone. When the player kills a Host, it will explode and leak out green Manticore-like liquid.
When it is a Host round, An-G will give the player(s) a warning over the intercom. "Attention, Contamination has been detected," signifying the Hosts are coming. In addition, the player's character will cough when a Host is nearby, alerting them to their presence.
If a player on co-op ends up getting killed by the infection, their character model will become an NPC Host and attack the other players as the player can watch in spectator mode. The player hosts are also much more resistant to damage than regular host zombies.
Hosts will always sprint, making it easy to prioritize them. Unlike other zombies, Hosts do not gain health as the game progresses.
- A Host can be seen in the Exo Zombies main menu by viewing the Outbreak scenes, where the camera shows the Host's right hand moving.