Buzzers are enemies from Hacx. They are dangerous floating robots with spikes on the lower side of their body.
Their only method of attack is using their spikes to hurt the player. They have 175 hit points, and since they can float they are hard to shake off. They are still somewhat fragile and can be taken down easily by most weapons. But when they attack in large numbers, it is best to take a safe distance as they can easily overwhelm and defeat the player. When they die, they explode like a barrel, capable of damaging anything near it.
There is a variant of the Buzzer known as Stealth. This variant behaves just like the original one, the only differences being that it is partially invisible and has less health. They can spell trouble for a surprised player, as even a single Tazer shot is enough to make it explode (possibly in the player's face).