“One of the Wasteland's most disgusting creatures, the Bloatfly shoots its maggots as projectiles, and often explodes upon death.”— Fallout 4 loading screen
The radioactive fallout resulting from the Great War mutated the tiny blowfly into the larger Bloatfly menace that is potentially lethal at a substantial range. They can be found all over the Commonwealth.
The standard bloatfly is covered in a green and brown carapace. It prefers to attack at long range, using its own larva (each of which sports a wicked dart-like spine) launched from the abdomen. An individual fly's supply of larvae is seemingly inexhaustible, and unless evaded or eliminated, the creature will pursue a target relentlessly. Bloatflies typically live in small groups of two to four individuals, but can be encountered on their own. Despite the increased size, they have no difficulty staying airborne.
Bloatflies in the Commonwealth will crawl on surfaces and display more aggression than their counterparts in other wastelands. Although they generally prefer a longer range to attack from, they will often fly very close to their target, which usually results in them doing more damage. They are almost always found in groups, and can become an annoyance due to their evasive movements when aiming at them. They tend to stay near bodies of water and swamp land, often accompanied by bloodbugs or stingwings.
These are one of the most common types of insect one will encounter at lower levels. They are usually found in groups of 2 or 3 and will only prove a real challenge to the already weakened or those at an environmental disadvantage.
A slightly stronger variation than their standard counterpart and are usually seen as part of a group, although they can sometimes be seen with other creatures such as stingwings or bloodbugs. Their distinguishing feature is a considerably darker carapace.
A festering Bloatfly can be found alone or in a group of other bloatflies or different types of creatures such as stingwings. They can prove a little tougher as they can endure more damage.
Glowing bloatflies are a hardier variant whose body emits a green glow caused by massive radiation exposure. Upon death a glowing bloatfly will explode with irradiated matter causing radiation damage to nearby life forms and may even damage and irradiate nearby crops giving them a radioactive glow.
Bloatflies are often seen stationary clinging to objects such as trees, walls and pipes. They can be found in sewers, in homes along the wasteland, or just along parks or wooded areas.
Bloatflies and bloodbugs do not seem to be hostile towards each other and occasionally appear to coordinate to both attack the player character at the same time.
When the Sole Survivor is pacifying a bloatfly, they will say things like "Hey, buzz buzz."
Bloatfly larva syringe can be used to farm legendary Bloatflies. The Bloatflies themselves are the source of materials for the syringe.
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