Indirectly related to Fatties, Bog Divers are an aquatic DiverANMC and are the smaller brethren of the Sea Diver. They have very good HP and only pop up when they are going to attack, limiting when they can be attacked (Even area-of effect PE spells will not harm them while submerged). Their electrical spit attacks can be difficult to predict and in most room where they are found, Aya does not have a lot of space to maneuver.
They are weak to Fire so Firefly rounds, Combustion and Pyrokinesis can kill them almost instantly. Without Energyshot, Firefly rounds can kill them in two shots, Combustion works (only if they are grouped up which rarely works) and Pyrokinesis works very well to boot.
On a couple rare occasions (Namely Shelter, Reservoir and Water Supply), they can be encountered in shallow water. Their movements are slow and they can only attack in close-quarters, becoming easy to defeat, provided you keep some distance from them.