I’ve dreamed about doing this one for a long time: a no-moon, no-lights dive on Lighthouse Reef. Roatan has amazing bioluminescence, and on truly dark evenings they can be as brilliant and numerous as the stars in a clear night sky. Tonight, I finally get my chance to do it.

We begin after sunset. As we descend down to the reef, I am amazed by how much I can still see in the waning light. Parrotfish nestle in to their holes and wrap themselves in mucus cocoons. Soldierfish and squirrelfish dart out from their alcoves. The reef is bathed in this eerie blue light that reminds me of hues I’ve only seen from Karl Stanley’s submarine. We careen through some canyons out the wall and chase the last remaining diurnal fish into crevices. The water column gradually fades into a slate gray as the sunlight dwindled.

Knowing that it won’t be long before the encroaching darkness envelopes the reef, we weave our way back into the shallows of Lighthouse Reef. Razor-sharp needles protrude precariously from the canyon walls. Hundreds of long-spine urchins— aptly named for their foot-long spines— are crawling out from their daytime hiding places, eager to feast on their nightly supply of algae and poop. Each needle-thin hollow spine is covered in thousands of microscopic hooks running the opposite direction of the spine that ensure the spine stays firmly lodged in a hapless diver’s leg. Not one for taking unnecessary risks, I hover higher above the reef than usual, no longer trusting my depth perception in the diminishing light.

We settle in at Lighthouse Reef’s sandy patch just beneath the mooring line. Hundreds of tiny, sliver-shaped fish, their species indiscernible in the dim light, hover at forty-five-degree angles one foot above the sandy patch like a rippling silver magic carpet. Two large permits zoom above— chasing, or chased?— audibly startling the school of slivers-shaped fish. The thin profile of a barracuda zips overhead, definitely chasing.

And then they’re all gone. The reef is still. The twilight feeding frenzy is over. Nothing but shadows and bubbles.

Sparks fly from my fingertips. Microorganisms, perturbed by the movement of my hands, fire glowing chemicals into the water in defense. The show has begun.

We kick off our fins and stand barefoot on the sand. ‘Come on,’ I taunt. He flies at me in slow motion, sparks flying from his body. I block the attack, grab his tank valve, and pile-drive him into the ground. A shockwave of glowing embers ripples across the sand. He recovers with an uppercut that launches me ten feet in the air. Arms flailing, I grab the mooring line, spin around, and deliver a fiery kick to his chest.

It’s Neo vs. Agent Smith, except without the crappy sequels.

I block his glowing foot. Fireworks explode at the impact. His punch lands squarely on my chest, catapulting me backwards onto the sand.

Cold water strikes my eyes. My mask. Crap, it’s fallen off. I open my eyes, but there’s no light. I’m blind.

I tap the sand around me but only find algae-covered rocks. I see the blurry shadow of my buddy ahead. “Lost mask,” I signal, followed by “I’m an idiot.” He swims away to search. I sit patiently, bubbles running out my nose. Man, it will suck if I have to end the dive because we were playing around. The best part is just about to start!

He drops the mask in my hand. I run my fingers along the plastic skirt of my mask, put it on my forehead, and exhale out my nose, clearing away the seawater so I can see. I blink my eyes open.

Thousands of stars burn against the vast darkness. I am in outer space.

Ostracods are tiny crustaceans— about the size of a tomato seed— that swim up from the deep at night to feed and, in the case of some Caribbean species, fornicate. As the male Caribbean ostracods swim through the reef shallows, they squirt a glowing chain of luminescent chemicals that resembles a string of Christmas lights. The males emit the chemical in a species-specific pattern that, like a Morse code, helps females of the species identify potential mates.

The end result of this massive invertebrate orgy is a phenomenon Roatan scuba divers call “String of Pearls.” On truly dark nights, the Caribbean Sea glimmers with millions of miniscule lights spontaneously appearing and vanishing. It’s way trippier than a Pink Floyd laser show and far more real than the hallucinogenic chemicals that inspired their music. Fortunately, divers can see String of Pearls twenty-six weeks a year on Roatan, as conditions are right during the waning lunar cycle from full to new moon.

I’m thirty minutes into the dive and my eyes have fully adjusted to the darkness. The sea is a soup of glowing lights. I swim freely about the sand patch, following the light gray contour of the sand along the black contour of the reef. Glowing lights stream eddy in front of my mask. I look behind and see my buddy’s entire contour illuminated with streaming bioluminescence. Any little movement causes an explosion of light.

The String of Pearls is now so thick that my sense of direction is affected. Spinning slightly with vertigo, I settle onto the sand, breathing slowly. Each bubbly exhalation blasts a whirling vortex of stardust into space. I mentally paint constellations across the galaxy of glowing stars spinning before me. For these precious few minutes, I am finally an astronaut.

The computer says it’s time to go. We follow the contour of the sand patch, our fins thrusting sparkling clouds in our wake. The bioluminescence flies past at warp speed. We spot the glow of the other dive group’s torch lights in the distance, join them at the boat’s mooring line, and make a slow, safe ascent.

We’re shouting excitedly as soon as we break the surface. “That was better than hanging out with rock stars!” exclaims my buddy. “Better than sex! Unbelievable!”

I laugh and lay back on my inflated BCD. Overhead, a meteor streaks across the pearly smear of the Milky Way. Below, bioluminescent nebulas tumble out with every fin kick.

And here I am: Major Tom, stepping through the door.

Dive No.: 1965
Dive Site: Lighthouse Reef
Max Depth: 40ft
Total Time: 54mins
Profile: 15mins @ 40ft, 39mins @ 20ft
Air: 210bar – 110 bar
Mix: air
Tank: 12L/80cu
Weight: 6lbs
Exposure: Rash Guard