The motor yacht Ballymena powers down and drops anchor in 12 feet of water. Regulators and dive lights get a final check, then we drop overboard for the short swim to the fringing reef. We negotiate a gap in a thick coral fortress, fighting a brisk current that wells up from the deep-blue gash within. We have come to experience one of the famed blue holes of Andros Island, and we have little time to waste. Within the hour, the outwelling current will go slack, then reverse and form a whirlpool that could draw unsuspecting divers into the depths below. BCs are deflated, dive lights are turned on, and we drop 40 feet down an irregular shaft. As surface light fades, the walls begin to expand outward. What was a pipe becomes an inverted funnel. We continue down, passing 60, 80, then 100 feet.At 120 feet, we touch down on a huge silt mound. The walls of the chamber are now 100 feet away on all sides. Perched atop the silt mound, sitting upright and remarkably intact, is a small island sloop, with mast stepped and remnants of the sail draped across the cabin top. An intentional burial at sea or the victim of Lusca? Bahamian lore tells how the breath of this mythical sea monster drives the inflow and outflow of blue holes, and few islanders will voluntarily venture into the monster's lair - even with the rich prizes of lobster awaiting. We drift deeper, knowing we must soon depart but wanting to catch a glimpse of the chamber floor. The absolute black of a cave tunnel looms at a depth of 160 feet. Nitrogen-fueled imaginations shudder at the prospect of a monster within, while the last remaining shred of common sense turns on the warning lights.We ascend for one more look at the wreck. The sun comes from behind a cloud and illuminates the far wall of the cavern, capturing a 100-foot-tall reverse waterfall of rising bubbles. Back at the entrance, we extend our safety stop to marvel at the miniature coral ecosystem that surrounds the hole. In an underwater desert of sand, this ring of life is made possible by the constant ebb and flow of water into the cavern entrance.The upwelling dies. Minutes later, the current reverses, and water is drawn over the coral ring and into the cavern mouth. Lusca is inhaling.