Wikipedia, its unusual name is thought to be from early settlers to North America who perhaps thought that it was a creature from hell bent on returning.
This is a very impressive salamander. The word "big" doesn't seem to do it justice. It can grow up to 29" (from snout to tip of tail.) Imagine that the next time that you are swimming in a stream in the eastern portion of the United States. There may be a 2 foot salamander down on the creek bed looking up at you. But, not to fear. They are harmless to humans. Humans are a much greater threat to them as they are listed as threatened in many parts of its range- including in North Alabama, where this specimen was found.
Hellbenders do not have external gills like another large salamander, the Mud Puppy. Instead, their gills are hidden beneath folds of their skin- hence their latin name which means- "hidden gills".
So what does the largest North American salamander eat? Anything it wants to. No, sorry. Hellbenders primarily feed on crayfish and small fish.
Wikipedia lists several other common names for this salamander. My favorite of the list is "Snot Otter". I really wish that "Snot Otter" had became the preferred name of this creature- I believe that it is more fitting than "Hellbender."
So, there you have it. Here we present to you- the Snot Otter. Maybe the name will catch on.