Kraken

There is nothing, beside storms and Sea serpents, which the old sailors fear more than the legendary Krake...

Normally this monsters of the deep... lives in the deep, but one time in their live a Gigateuthis must come near the surface.
namely when they lay eggs. The females swim towards the sun and spread their eggs in warmer currents of the upper layers.

Encounters with humans were often inevitable...

Monster squid size chart:[link]