Cryptids

Cryptids are the main enemy of the Extinction game mode in Call of Duty: Ghosts. They were unearthed in Colorado following the events of Ghost Stories.

In Call of Duty: Infinite Warfare, there are references to them in the Zombies game mode.

Origin
The Cryptids originated before the dinosaurs, when Earth was a huge planet of gas and fumes. The skies were stained black from countless volcanic eruptions. Sometime later, a comet ignited the oxygen from the atmosphere, causing a devastating fire storm that incinerated all life on the surface of the earth. The Cryptids foresaw this catastrophe, and devised an ark to ensure their survival of the ancient apocalypse in an underground cave area under Colorado. It was only after an ODIN Strike, due to the Federation taking control of the orbital weapon, that the cave was unearthed. Now free, the Cryptids swarmed the surrounding area, killing everything in their path.

Known Types of Cryptids

 * Scouts are mere cannon fodder and are the smallest and weakest species of the Cryptids. They prance on four legs and attack the player and the drill. Though they may be weak alone, in groups they can take down any amount of armor.
 * Scorpions are an odd species within the Cryptids, as they pose very little similarity to the rest of the species. Scorpions are large aliens who use their large tails to shoot a powerful, noxious green gas that can choke and poison the player within a small area.
 * Hunters are essentially evolved Scouts, sharing a very similar body shape, albeit three times larger. They can run on two legs in a charge or they can run on all four. They have the most amount of health, same for the Rhinos, and can inflict massive damage toward the player and the drill if not dealt with immediately.
 * Seekers are another odd species as they are a small, sphere-shaped alien that are able to self-destruct. Seekers will always appear from a fallen meteorite (Except in Mayday) and will immediately begin to seek out the player and drill in the hopes of inflicting damage.
 * Rhinos are an extremely powerful and evolved Cryptid that can prove to be a great challenge. The Rhino has an armored hide that makes it resistant to gunfire. Rhinos are known to run on their hind legs and fists in order to catch the player. They are able to charge at the player and slam the area near them to try and inflict shock damage.
 * Lepers are a unique and rare evolution of the Hunter. The Leper is unique as it is the only cryptid that intentionally runs away from the player. The Leper will only spawn when the "Find and kill the Leper in 30 seconds" challenge has begun.
 * Phantoms are a breed of cryptids introduced in Nightfall. Phantoms are the next step in evolution for the Hunters. This allows the Phantom to become stronger and gives it the unique ability of turning invisible when it jumps.
 * The Breeder is a dangerous breed of Cryptid introduced in Nightfall. The Breeder is a large, spider-like creature that easily towers over the player. The Breeder possesses several different attacks. It can use its razor sharp claws to try and kill the player and can also shoot a gas similar to that of the Scorpion. The Breeder possesses a unique machine gun attack that can damage and kill a player very quickly. Like its name suggests, the Breeder can lay eggs that will spawn more Cryptids. So far, the Breeder is the first and only Cryptid with its own health bar (with the exception of the Kraken)
 * Seeders are a breed of cryptid introduced in Mayday. Seeders have the ability to shoot toxic gas clouds like the Scorpions, but also can shoot out pods that grow into mutated plants. These plants will act like turrets. These plants can be killed or kept from growing if the pod they spawn from is destroyed. Seeders are the only cryptid encountered to walk across ceilings. Seeders seem to visually resemble Seekers and act as a replacement for the Scorpion in Mayday.
 * The Kraken is a dangerous breed of cryptid. The Kraken gets its name from the famous folklore of a huge sea monster, referred to as a Kraken. The Kraken was seen at the end of Nightfall's epilogue teasing the next map. The Kraken is by far the largest cryptid encountered in the game thus far. It is the only cryptid that is water based, but there were smaller, squid-like cryptids seen in Nightfall's epilogue that have not been seen in Mayday's trailer or mentioned by the Infinity Ward staff. The Kraken is the boss of Mayday, just like the Breeder was in Nightfall. The Kraken does have an earlier appearance in the map Mayday as its tentacle bursts through the hull of the ship, spitting out enemies.
 * Gargoyles are a unique Cryptid introduced in Awakening, as they can fly. They have a high amount of health, and they damage the player by shooting projectiles from their tails
 * Bombers are a breed of Cryptid introduced in Awakening, are extremely similar to Seekers, except they have the ability to fly. They will idly fly for a few seconds, then they will charge at the player and explode.
 * Mammoths are a large breed of Cryptid that is introduced in Awakening. They are extremely similar to Rhinos, except they have a blue glow the ability to dig underground and emerge in the player's location, the ability to summon Hunters to assist them, and are also extremely durable and strong (more so than the Rhino). It is the Cryptid seen on the Background earned from escaping Point of Contact with 3 Relics Active.
 * Ancestors, shown in Mayday's epilogue and in Awakening, are the "masters" the Cryptids serve. They telepathically communicate with the cryptids, giving them orders. Seen in Awakening's intel, Captain Archer kills one and uses the Ancestor's brain to create The Cortex. The Ancestors have used humans like Samantha Cross as spies, preparing to end the human race and take back Earth.

Cryptid Hives
After the standard Cryptid sub species are the hives. The hives are a fungal conglomeration that reach deep into the earth's core to tap into the rich geothermal energy which they use over a source of light. The hives have the ability to rapidly regenerate lost cells, making destroying them nearly impossible without the use of Laser Drills. By releasing pheromones in order to communicate with the Cryptids, they in turn protect the hives.

Trivia

 * There are several references to them in Infinity Ward's Zombies mode. The same exact team that worked on Extinction worked on that Zombies mode too.