Mokele Mbembe
The Mokele Mbembe is a legendary creature from the Bantu mythology. Rumored to inhabit the rivers of the Congo River basin, this cryptid is often described as a giant, dinosaur-like monster resembling a sauropod. In the Lingala language the name of this monster loosely translates to "the one that stops the flow of the river".
Local tribes tell tales of its enormous size similar to an elephant it has a long neck, and a territorial nature that has supposedly sunk boats and killed crews but never ate any of the bodies. I believe its entirely possible for a prehistoric creature like this to still exist in very small numbers considering the immense deforestation in some areas that has lead to discoveries of giant creatures once hidden in the brush.
There been no confirmed specimens, which puts it inline with many cryptids however the myth of this beast carry's on with many new sightings. There are many explanations for this creature including the idea that the long neck is actually just the trunk of an elephant in the distance and the capsized boats with intact bodies could just be from charging hippos. The truth however for now will stay unknown..

