Bloatfly (Fallout 3)

A Bloatfly is a common mutated Capital Wasteland pest resembling an oversized blow-fly. While a reasonable source of experience for greenhorn explorers — due to their weakness and the ease of avoiding their attacks — Bloatflies become little more than pests for even novice players.

Behavior
A common encounter in the Wasteland, the comparatively diminutive Bloatfly is quite aggressive, often attacking animals much larger than itself with reckless abandon. Bloatflies do not attack at close range, but rather keep to a standoff distance and pepper their prey with spine bedecked larva launched from its abdomen. The supply of these larva is seemingly inexhaustible, and unless evaded or eliminated, Bloatflies will persecute an attacker with relentless single-mindedness. When attacking, Bloatflies emit a high-pitched cry. A wanderer more than a dozen feet away will likely not hear the fly's call before being attacked. Individually, they do not inflict much harm, but in packs Bloatflies can be a serious nuisance to explorers and potentially deadly to weaker companions.

Bloatflies typically live in small groups of two to four individuals, although lone bloatflies are also common.

Combat with Bloatflies
Primarily a low-level encounter, Bloatflies are second only to the ubiquitous Radroach as weakest enemy encountered in the Capital Wasteland. Bloatflies can generally be killed with only one or two shots from a firearm.

Killing a bloatfly is, compared to most Wasteland animals, straightforward and safe to all but the weakest wanderers. While it is possible to hit a bloatfly "on the wing" by live-firing a weapon, the animal's annoying tendency to jink and dodge makes targeting difficult. Using V.A.T.S. with a low-use-cost weapon is the most efficient way to kill a bloatfly. Since a single round is typically adequate to kill a bloatfly, automatics, such as the 10mm SMG or Assault Rifle, waste two to four rounds of costly ammunition when engaging a Bloatfly. The 10mm Pistol or Hunting Rifle, both of which consume plentiful, inexpensive ammunition, are thus more economical choices when killing Bloatflies. Naturally, any single-shot weapon is more cost-effective in terms of ammunition expended, so using an overpowered weapon such as a Scoped .44 Magnum is a waste of expensive ammunition. Though for all intents and purposes the most cost effective and entertaining alternative to shooting one would be running headlong at it or bobbing and weaving until a V.A.T.S assisted punch can be thrown.

However, bloatflies are slow-moving for insects, and unless over-encumbered, can be avoided simply by fleeing on foot. While outdistancing a bloatfly does not take long, the animal can strike several times before a safe distance is reached. To that end, running in a zig-zag pattern to throw off the fly's aim is generally the most effective way to avoid being stung also try jumping around a bit if this does not work you may still get hit but there is a 0% chance of it scoring head shots