Boom Flies are much larger than normal Flies and are considerably faster as well. Rather than trying to follow you, they will instead fly around the room diagonally, bouncing off walls. They have considerable health, taking at least six initial tears to go down. They deal usual 1/2 heart damage on touch, but they will explode on death, typically killing all other monsters and dealing a full heart of damage in a two-square radius. Boom flies usually appear in groups: Beware of chain reactions from multiple boom flies.
Keep in mind that the Skatole item will NOT defend you from a Boom Fly explosion, although it does SLOW the boom fly drastically.
Red Boom FlyEdit
This variant behaves in the same way and has the same stats, but will shoot 6 projectiles on death instead of exploding. The projectiles ALWAYS have a set trajectory pattern so you can position yourself for safety.
Possible bug: If you kill a Red Boom Fly before it starts moving, it will explode like a normal Boom Fly but still shoot its projectiles.