I've just returned from Durban, South Africa's friendly east coast port city blessed with a warm sea and world-class surfing waves.
It's also cursed - with one of the most insidious little drugs I've ever come across.
Whoonga, as it's known, is a substance being smoked in poor township communities around Durban, and it's popping up in other parts of the country as well.
Drug-taking is commonplace in the townships - what else do you do if you're unskilled, uneducated and unemployed, as so many are?
Backroom experimentation produces an ever-changing array of concoctions that offer a cheap and lethal high.
What makes whoonga different - a fine white powder, added to marijuana and smoked - is its composition.
It's a blend of detergent powder, rat poison and, crucially, crushed up ARVs, or antiretroviral drugs distributed free to HIV sufferers.
With South Africa finally making inroads in the battle against HIV and Aids after years of denialism, this is a dreadful blow.
Whoonga is cheap, bought from a dealer for just 20 rand or $3 a hit. But 40 per cent of all South Africans survive on little more than $2 a day.
The average jobless whoonga user needs multiple hits to get through the day, so for many crime becomes the only way to secure a regular supply.
Worst of all, it means people in need of ARVs to save or prolong their lives are sometimes going without.
They're being mugged for their pills as they leave the clinic.
Some are willing to sell them - the free ARVs now have a value more pressing to the poorest than even their lifesaving properties.
Clinic staff are reportedly being enticed to sell ARVs directly to dealers and addicts.
And if that's not shocking enough, perhaps the very worst aspect of whoonga is that many addicts, I'm told, actually seek to become HIV positive, because then they'll get their supply for free. No need to bother committing a crime.
The authorities are well aware of whoonga. The police and the national addiction council say they're doing what they can.
But with whoonga production and supply taking place behind closed doors in the rabbit-warren streets of townships blighted anyway by huge levels of crime, prioritising whoonga is a challenge.
With limited resources to turn the tide on ignorance among the ill-educated, officials admit efforts to promote awareness are not enough.
One group is making a difference, albeit a tiny one.
Vumani Gwala runs Project Whoonga, a community support group operating in one small corner of a giant township outside Durban called Kwadebeka, where whoonga thrives and grows every day.
Gwala has 45 addicts in recovery, persuaded to face months of excruciating withdrawal for the promise of being taught a new skill, like furniture upholstery.
They're trying to get their lives back, and encouraged to educate the community.
But this is a tiny charity army, with miniscule funding raised mostly within the local community, fighting a cruel and instantly addictive drug.
There are no figures available yet for the scale of whoonga use, but Gwala estimates it's easily in the several thousands in Kwadebeka alone.
Project Whoonga needs all the help it can get. Contact them at www.whoonga.za.org