The resulting radioactive fallout after the Great War mutated the tiny blowfly into the larger bloatfly menace that is potentially lethal even at medium to long range.
Characteristics
Biology
Bloatflies attack at long range by shooting their prey with spine-bedecked larva launched from its abdomen. This supply of larva is seemingly inexhaustible, and unless evaded or eliminated, bloatflies will persecute an attacker relentlessly. They are covered in a green-brown carapace. Bloatflies typically live in small groups of two to four individuals but can be encountered on their own.
Game attributes
Individually, they do not inflict much damage, but in swarms, bloatflies can be a moderate threat to low level players and deadly to weak companions.
Their carapaces are not particularly effective when trying to protect against any type of weapon, thus they are easy to kill, assuming you can hit them. Due to their erratic movements, bloatflies can be challenging to hit at times.
These creatures are found throughout the wastes but they are most commonly found in areas nearest to where barrels of radiated material seep into the soil.
A bloatfly's wings makes a faint clicking noise, a bit like a giant ant's movement, but fainter.
Bloatflies, when they do not see you, seem to do circles in the air then stop, making it somewhat easier for the player to target them outside of V.A.T.S.
Bloatflies are one of the weakest creatures to come across in the wasteland, on par with radroaches for being the weakest enemies in the game.
On death, they make an interesting high-pitched chattering noise.
Yao guai are for the most part non-hostile toward bloatflies. The reason behind this is unknown.
The Enclave outpost near Megaton has been studying these and other creatures native to the region.
In a piece of concept art by Adam Adamowicz, the bloatfly is referred to as a "Shrieking blowfly".