Deep One
"I think their predominant color was a greyish-green, though they had white bellies. They were mostly shiny and slippery, but the ridges of their backs were scaly. Their forms vaguely suggested the anthropoid, while their heads were the heads of fish, with prodigious bulging eyes that never closed. At the sides of their necks were palpitating gills, and their long paws were webbed. [...]

Their croaking, baying voices, clearly used for articulate speech, held all the dark shades of expression which their staring faces lacked ...

They were the blasphemous fish-frogs of the nameless design - living and horrible."

H. P. Lovecraft, The Shadow Over Innsmouth

Bryan Wynia's course is very popular, as the number of Deep Ones on the web is constantly increasing; it's incredible the variety of different designs that can be pulled out from the brief, terrifying description given by the author.

Here's my take on this creatures.

Speed sculpts, made in about one hour: