Where's My Brain

There was once a man, That left his brain at home, That wouldn't really had known, That a beast was lurking alone. That a feast was all that was home. In the depths that was sea, A monster living naturally, An abomination of man, Searching for it's homeland. That man didn't know that the depths would reach so low, Now is that man alive, Can that man breathe under pressure would one know lies? Kraken..... swept away, That man never returned home