An impressive example of the mutations caused by the Great War, the bloatfly is an evolution of the Tabanus genera of biting horse fly. Tentatively classified as part of the Tabanidae family in the order Diptera, class Insecta, phylum Arthropoda, and kingdom Animalia, it is a major divergence from its evolutionary forebears.
The standard bloatfly is covered in a green and brown carapace, it is significantly larger and more tenacious than its predecessor the horse fly. Although its size inhibits its flight characteristics and agility, making it impossible to feed like pre-War horse flies did. Instead, it uses its engorged stinger and pupae gestating within its abdomen to incapacitate prey. The stinger is capable of launching mature larvae with a barbed sting at the end. These latch onto the target and deliver a neurotoxin capable of incapacitating larger prey, allowing the bloatfly and its larvae to feed. Its neurotoxin is ineffective against humans and larger targets, with localized necrosis being the only larger complication. As a result, the bloatfly is frequently prey, rather than predator, particularly among wastelanders who learned how to prepare its meat (or can stomach eating it raw). Some are noted to explode upon death. Bloatflies can resort to scavenging in situations where prey or other sources of food are scarce. It adapted to its enlarged size with a unique gland that enables it to balance and maintain speed despite its size. The gland itself may be toxic to consume.
The bloatfly is a giant mutated blowfly. Bloatflies attack at long range by peppering their prey with spine-bedecked larva launched from its abdomen. They tend to attack in groups, and their ability to attack from a distance can make them significantly dangerous at low levels.
↑ 2.02.1The Sole Survivor: "Sign me up." Duff: "You're going to go out, and find a Bloatfly Gland. You see, the oversized Bloatfly of today evolved from an earlier species of smaller fly. Radioactive adaptation has resulted in a unique gland that enables it to balance and maintain speed despite its size. So what do you say? Ready to go out and dissect one?" (DoctorDuff.txt)
↑Fallout 4 loading screen hints: "One of the Wasteland's most disgusting creatures, the Bloatfly shoots its maggots as projectiles, and often explodes upon death."
↑The Sole Survivor: "Get the Bloatfly Gland. Got it." Duff: "Remember, bring the gland back in one piece. Oh, and don't chew on it. One of the students got horribly sick because of that mistake." (DoctorDuff.txt)