Beneath the glistening surface of the water, mere meters below their vessel's keel, a colossal shadow, as dark as midnight, surged forth from the abyss. It was an enigmatic entity, both awe-inspiring and terrifying. This otherworldly apparition made its fleeting appearance, a mere three to five seconds in the inky depths.
"Dear God, what in heaven's name was that?" quivered one voice, trembling with fear.
"Mom, I was positively petrified! What on Earth was that?" cried another, the anxiety in their voice palpable.
"At least three hundred meters in length, it couldn't have been a sea snake. There's nothing known to man of such staggering proportions," declared a third voice, grappling with the inconceivable.