Bloatfly (Fallout 3)

A Bloatfly is a mutated fly. Bloatflies can be found throughout the Capital Wasteland area. A shrill scream serves as the only warning before this over-sized pest delivers a colony of maggot eggs into your belly via its stinger-like projectiles.

Bloatflies are the second weakest enemy encountered in the Wastelands (Only encompassed by the Radroach) and can be easily avoided by running.