Iz and Carl watch helplessly as Rex slips over the side.

“Carl, grab an oar. We’re moving the boat.”

The sea is so visible that Rex feels like he is swimming toward the underwater lights of a deep swimming pool. He hovers six feet below the hull, feeling totally at peace, his body and escaping air bubbles immersed in the soft, emerald green glow.

Movement above his head causes him to look up. My God …

Rex blinks twice, staring incredulously at the grotesque creature that has attached itself lengthwise along the center of the Manatee’s keel. Thirty-five feet of willowy tentacles flow from a caterpillar-like girth of gelatinous goo. No less than one hundred bell-shaped stomachs traverse the creature’s cream-colored, ropelike body, each digestive aperture containing its own hideous mouth and poisonous, fingerlike projections.

Incredible. Rex has never seen a live specimen before, but he knows the creature is an Apolemia, a species of siphonophore. These bizarre life-forms, which can grow upwards of eighty to one hundred feet in length, inhabit only the deepest waters and, as a result, are rarely seen by man.

The light must have chased it to the surface.

He snaps several pictures, remaining at what he hopes is a safe distance from the creature’s poisonous stingers, then releases air from his BCD vest and descends.

The surreal lighting gives him the strangest sensation of falling in slow motion. Rex scissor kicks at sixty feet to slow his descent, the pressure building within his ears. He pinches his nose and equalizes, surprised to find the pain getting worse. Then, looking down, he notices something rising at him from the luminescent void.

Rex smiles and extends his arms as thousands of Volkswagen-size air bubbles ascend all around him.

Incredible.

The sinus-cavity pain forces him to refocus. A dull baritone roar fills his ears, causing his face mask to reverberate and tickle his nose.

Rex Simpson stops smiling as he registers a gut-wrenching feeling in the pit of his stomach, a feeling similar to being suspended at the summit of a towering roller coaster just as it begins its downward plunge. The roar gets louder.

It’s an underwater earthquake!

Two thousand feet below, an enormous section of the limestone seafloor collapses in upon itself, revealing a gaping tunnel-like aperture. The sea begins swirling as it is sucked into the growing hole, the torrent drawing everything into its plunging vortex.

The emerald green light intensifies, nearly blinding him.

Iz and Carl have managed to paddle the Manatee to the perimeter of the brilliant patch of sea when an unseen force seems to grip the stern, dragging the fishing boat backward. The two men turn, horrified, the sea now churning in a great counterclockwise vortex.

“It’s a whirlpool! Paddle faster!”

Within seconds, the Manatee is caught, moving backward along the outer edge of the maelstrom.