A. Why was the Giant Squid beached? Does this happen spontaneously, when the creature becomes to old or too large to sufficiently feed itself?
B. Is there much difference between a huge squid and a large octopus?
It may have tangled with a whale, or other predator, and lost.
Octopi have a rounded body; squid have an elongated body. At least in the cartoons, where I got most of my knowledge, as a kid.