Radroach

Great American cockroaches, colloquially called radroaches or giant cockroaches, are giant versions of the pre-War species that have been mutated by atomic radiation.

Characteristics
Found mainly in underground areas and sewers across North America, which can cause them to be a pest in certain Vaults because they can usually be found in fairly large groups. They feed on the dead but will go after living creatures if isolated. Their numbers are their biggest advantage. Radroaches live mostly in the areas east of California.

These radroaches are commonly found in the dark, damp and irradiated parts of the wasteland and look similar to normal cockroaches, save for the fact that they have mutated to be the size of the domestic cat. They are generally little more than a nuisance to Armageddon survivors and are less than likely to pose a challenge. Radroaches are territorial and rather aggressive, but not very harmful. Anyone can kill them with their bare hands, and will only attack when they feel threatened by passersby. Although they are winged, they are incapable of flight, likely due to the wing appendages failing to adapt to the rapidly changing body mass. Still, it is possible that the wings are used for inter-species communication. Radroach innards are useful in the treatment of radiation poisoning and are widely used by tribals for this purpose.

Radroach


These radroaches are commonly found in the wasteland and look similar to real-life cockroaches. Radroaches were enlarged extensively by mutation, to the point that they are now as large as house cats.

They are generally little more than a nuisance to Wasteland survivors and are less than likely to pose a challenge. Radroaches are territorial and rather aggressive, but not very harmful. Anyone can kill them with their bare hands, and will only attack if you are very close; despite this, Vault 101 security personnel usually are no match for around 3 radroaches at once and will be easily disposed of. This is seen during Escape!

On one of the childhood quests in Vault 101, the Lone Wanderer, on their 10th birthday, is tasked with killing one with a BB gun given to them by Jonas Palmer as a birthday present.

Irradiated radroach
The irradiated radroach is identical to the standard radroach, with the exception of a radioactive aura, similar to that of a feral ghoul reaver. In addition to this, they hold the ability to heal themselves with a radiation blast similar to a glowing one. On death, it drops irradiated radroach meat, which gives extra radiation when consumed.

Giant cockroach


In the Midwest, mutant cockroaches are a common sight in the Wasteland. As in the Capital Wasteland, they can be encountered nearly everywhere, from old buildings to plains. However, they are drastically different and more dangerous than those met in the Capital Wasteland. They have a big, protected main body and small legs, and their saliva is incredibly toxic. They are very aggressive and attack every human unlucky enough to encounter them.

The Midwestern giant cockroaches are more varied than their Capital Wasteland cousins. Their size can also vary - they can be as small as their relatives in the Capital Wasteland or as big as an adult human.

Roachor


Roachor is a unique giant cockroach encountered by the Warrior of the Brotherhood of Steel. It is an "advanced" version of a large cockroach, which lived in the Peoria facility. It appears Roachor was affected by the high amount of radiation coming from a strange production device that was used in manufacturing fusion batteries. He is bigger than any large radroach, the same size as a car, and his body glows with greenish radioactivity. His poison is deadlier than that of Midwestern radroaches.

Appearances
Radroaches appear in Fallout 3, Fallout: New Vegas, Fallout 4, Fallout 76, Fallout Tactics and Fallout Shelter, and were to appear in Van Buren. They were also mentioned in Fallout Bible 1.

Behind the scenes

 * Regarding creating radroaches for Fallout Tactics, Tony Oakden stated in an IGN interview, "We also have giant cockroaches cos [sic] we understand that in the event of a nuclear was [sic] they will be the most likely to survive and as every one who watches 50s sci-fi knows they will mutate to enormous size (we took the liberty of introducing a venomous spit)."
 * In real life, roaches are about five times more resistant to Grays of radiation than humans, but some scientists have regarded the popular notion of roaches being able to survive the apocalypse as "mostly an urban myth."