Imagine you’re trundling along, minding your own business when all of a sudden you find yourself engulfed in a literal whirlwind of poo.
Sounds mercifully unlikely, but that’s exactly what happened to this group of divers after they encountered a sperm whale as they explored the waters off the small island of Dominica.
Describing the filthy act as a “poonado” Canadian photographer Keri Wilk, 30, told how the mammal managed to create a veritable whirlwind of excrement by spinning onto its side and flapping its tail.
One minute you're swimming through the crystal-clear waters of the Caribbean, the next you're engulfed in a torrent of poo
The behaviour is believed to be evidence of a rarely-seen defence mechanism in that the resultant brown mist - in this case stretching 30m in diameter - could obscure the animal from predators.
The unique experience was somewhat blighted for Wilk however, who revealed he was wearing just goggles and a snorkel – having eschewed scuba diving equipment so as to avoid disturbing the beast.
He said: "Four of us got into the water near the whale, then it slowly approached us, stopped, and pointed itself straight down before the storm began.
"At first, it seemed like a regular bowel movement but rather than continuing its dive down, it remained at the surface and continued to defecate for a startling length of time.
It is believed this could be evidence of a defence mechanism
"Four of us looked at each other with confusion, then back at the whale, expecting that any second its call from nature would come to an end.
"Instead, the whale bobbed up and down, spun in circles and waved the poo in every direction for several minutes while we just sat back and watched.
"The water was crystal clear, initially, and was the most idyllic Caribbean blue water that you could imagine.
A pre-poo moment
"After a few waves of faeces were released and stirred vigorously by the whale, the water was like chocolate milk, I couldn't see my hand when I held it in front of my face.
"I had poop in my eyes, mouth, wetsuit, everywhere and I was soaked in it from head to toe.
"But, after leaving the cloud, it quickly washed away, and didn't leave a smell on us.
"I did take an extra long shower once I returned to shore later that day, just in case.
"I've never heard of it happening before, and I don't know anyone that has had this happen, it very well could be the first time that it has been photographically documented."