Thank god the real giant squid stay in far, far deeper waters. "Scientists who know everything" estimate that they are about 13m (43ft) long, with eyes the size of dinner plates. Now imagine of one of those guys took a little nip at yah. Would break your back before your wrist.
I could go on and on posting far more terrifying creatures from the deep here, but to sum it all up: of all the places on earth, I find the ocean to be the most terrifying. Would far rather be stranded in some desert or jungle before the ocean, if you only take into account the local wildlife.
Also, it is pretty dumb that the guy in that video thought he had fended them off by simply flailing about, and then was surprised when they came back for more. A human in water is about as helpless as a fish out of water.
If I've got time later, I will post some of the freakiest shit you will ever see right here.