from 's 28 monster challenge

a monster that spreads a specific disease

the Bogglefly is a monstrous creature of unknown origin, it shows up in small towns and villages where it perches on the tallest building it can find. Once a Bogglefly is present the air in and around the village becomes foul and any who breathe it slowly go insane. Long term exposure results in physical deformation, the face and limbs of the victim are covered in luminous boils which burst upon death, spreading the disease to anyone in range. The Bogglefly uses the skulls of expired afflicted as casings for it's larvae, it is also said that if slain the Bogglefly spreads a cloud of microtic dormant eggs into the air to disperse into regions unknown. This trait combined with the extreme violence of it's enthralled victims make the disposal of a Bogglefly a task best left to experts.