Anglers are mutated creatures with fleshy bioluminescent growths atop their heads (similar to an anglerfish's illicium) that acts as a camouflage for the predators, effectively disguising them as the surrounding lure weed to fool its prey. They are most likely mutated anglerfish or frogs, sharing the "lure" and upturned jaw of the former, and the limbs, proportions and habitat of the latter.
The angler is an aggressive creature with the ability to absorb the fog and spit it out like a fireball, inflicting incendiary damage to any target it is able to hit. In combat, they often rely on these long ranged attacks, but have been observed to charge at their prey and use their claws, though often they will halt mid charge to use their preferred method.
With the means to use V.A.T.S., travelers can spot these creatures hiding among lure weed and avoid a surprise attack. Without this ability, the angler's illicium can be distinguished from the plant by the lack of leaves of a single appendage resting on the water's surface. Sometimes, the angler's head can be visible under the surface and mistaken for these leaves from afar, but will remain submerged until the prey is close enough. Getting too close will alert the angler, causing it to spring from the water and engage.
Anglers' energy resistance is much higher than their damage resistance, making ballistic or melee weapons the preferable choice for engaging them in combat.
Anglers will not enter buildings or climb stairs. If a player enters a building the angler will retreat but stay in the general area. Anglers will use their ranged attacks against players that they cannot get close to but will retreat if attacked with ranged weapons from a position that they cannot get to.