Although this looks like Enhydris plumbea, its scale count is unusual. Could it be Homalophis doriae? It was found in a gravel stream in Temburong, Brunei, in the early hours of morning.

Very aggressive and powerful. It is capable of twisting its body and neck to a point where you would expect it to cause death. Yet, it continues in this manner with impunity. It was filmed moving from the stream bank into the water, when it released a good deal of air, a plume of air bubbles streaming from its nostrils. Despite the pool's small size, it vanished and could not be relocated! The bite was powerful, resulting in numbness and, later, itchiness.

Watch the diving clip here:

https://www.instagram.com/p/C24n8Y1hFm3/?igsh=MTdmeGEza3ZyM2MwNg==