List of Earth creatures

The Half-Life cockroach.

The three crow chicks under GLaDOS' care in Peer Review.

Apart from the Xen, Race X and Synth creatures, Antlions or Combine Advisors, the Half-Life and Portal series feature Earth creatures as well. They are either heard, mentioned, or appear as actual NPCs.

Lists by game series[edit]

Creatures
Antlions	Antlion · Antlion Grub · Antlion Guard · Antlion Guardian · Antlion Soldier · Antlion Spitter · Antlion Worker
Headcrabs	Headcrab · Classic Headcrab · Armored Headcrab · Fast Headcrab · Gonarch · Poison Headcrab · Reviver · Headcrab Shell
Race X	Gene Worm · Pit Drone · Pit Worm · Shock Roach · Shock Trooper · Spore Launcher · Sprite · Voltigore
Synths	Synth · Advisor pod · Crab Synth · Combine Advisor · Combine Dropship · Combine Gunship · Hunter · Mortar Synth · Strider
Xen	Alien Craft · Alien Controller · Alien Grunt · Barnacle · Boid · Bug · Bullsquid · Chumtoad · Clam · Gargantua · Gnat · Headcrab · Houndeye · Ichthyosaur · Leech · Nihilanth · Protozoan · Snark · Tentacle · Vortigaunt
Zombies	Zombie · Classic Zombie · Fast Zombie · Gonome · Jeff · Poison Zombie · Revived Zombie · Zombine
Other	List of Earth creatures (Half-Life series / Portal series) · Mantis Man
Antlions (cut)	Antlion King
Synths (cut)	Attack Synth · Combine Guard (Synth) · Combine Mobile Mine · Combine Super Soldier · Combine Synth Elite Soldier
Xen (cut)	Archer · Charger · Fast Walker · Flocking Floater · Jelly Bobber · Kingpin · Mr. Friendly · Panther Eye · Sand Barnacle · Snapbug · Sphere · Stukabat
Zombies (cut)	Zombie Assassin · Zombie Monkey
Other (cut)	List of minor cut creatures · Blob · Hydra · Particle Storm · Sacktick · Skitch