Unidentified underground creatures consume livestock and the human residents in the town and surrounding valley.
The blind, worm-like animals travel effortlessly through the Pleistocene alluvial soil, tracking prey by means of sonic vibration.
Townspeople terminate the creatures with crude homemade weapons. Existing specimens badly damaged and decomposed. No living animals found for study.
Creatures become widely known as Graboids.
Graboids appear in the oil field. Company employees are consumed and oil production is interrupted.
Desperate oil company executives hire survivors from the 1985 Graboid attack to track down and kill the Mexican Graboids.
On site Geologist Kate White reports Graboids are extremely ancient earth life form.
Before all Graboids can be eliminated they undergo a highly unusual metamorphosis sub-divding into smaller bipedal surface creatures. Technically blind like the Graboids, these creatures nevertheless efficiently track their prey by sensing heat. Some humans survived by devising methods to disguise their body heat, including using cold blasts from a CO2 fire extinguisher.
These new creatures become known as Shriekers due to the piercing cry they make when sensing prey.
Shriekers are reported to be hermaphrodites, reproducing by regurgitating an offspring immediately after the consumption of a meal. This has not been confirmed.
Note: If Shrieker reproductive rates are shown to be directly proportional to available food supply, a Shrieker “population explosion” is a potential threat.
According to survivor Burt Gummer, all Chiapas Mexico Shriekers were eliminated by use of an “appropriate” amount of high explosives. All remains badly damaged and decomposed. No living animals found for study.
Graboids appear in remote area.
Radical Graboid hunter Burt Gummer, survivor of both previous Graboid attacks hired by Argentine government to deal with the situation.
According to Gummer, Graboids had already changed into Shriekers before his arrival. Gummer slaughters over a hundred Shriekers with an antiaircraft gun.
All remains badly damaged and decomposed. No living animals found for study.
Graboids reappear in the town of perfection just after former resident Melvin Plug started attempting to buyout local residents to turn the entire town into a housing project called Perfection Valley Ranchettes.Burt Gummer and the rest of the town rally to destroy the new hoard of creatures but the United States Department of the Interior steps in and orders a Graboid to be captured alive.
Before they can capture a Graboid alive the creatures turn into Shriekers and then again into flying creatures that propel themselves into the air using a chemical reaction generated in their abdomen (tail).
Another unusual development in this outbreak is that one Graboid was born an albino and seems incapable of metamorphosing into a Shrieker. This great white Graboid becomes knows to the townspeople as El Blanco.
El Blanco is left alive and the United States Department of the Interior deems Perfection Valley a protected area preventing Melvin Plug from developing his Perfection Valley Ranchettes.
Now the people of Perfection are living with a graboid and who knows what else will come there way…