The original monster from the Greek myths is called the Cetus.
I'm not sure what he supposed to look like, but I believe he is placed among the stars after Perseus slew him.
The Kraken is more of a giant squid.
Somewhere around here, I have a book with a Kraken pictured in it, about 5 times larger than a blue whale! I would think something like that would make quite a splash washing up on shore! Do you have a link to an article about that Myrddin? You have me scared to go swimming now! How big was this one they found?