It's called a goonch, and it's a catfish that can get really big and is said to be eating people in India and Nepal.
The story is strange. The goonch probably started down the path of eating people by scavenging bodies disposed in rivers in the area, a common practice apparently. Now, some mysterious cases of disappearing people are attributed to a goonch pulling them underwater and eating them.
This is no run-of-the-mill catfish, they're BIG. They can get to be 200 pounds and they are certainly capable of pulling a person underwater. In one case of a disappearing Nepali boy, he was said to be pulled underwater by "an elongated pig." I suppose a goonch could be described as an elongated pig (see photo above).
The goonch that ate people, sounds like a Dr. Seuss book.
Hat tip: zooillogix