Maumee River Monster is a river monster, it was first reported circa the 1970's. The man who reported it was Sam McConnish, who claimed he saw the river monster and a Thunderbird. It usually is said to look like Nessie or a giant catfish, though it's stated to be a serpent more often than a giant catfish. In 2009 a man who was by the mouth of the Maumee River reported a large sea serpent like monster and it had quickly disappeared into the water.
It should be noted that a person seeing more than one cryptid during their lifetime is an extreme rarity, and seeing two at once is can therefore easily be regarded with suspicion. This leaves the likelihood of this specimen being real as being very low, or at least that the original claim of the creature being a hoax was significantly high.