Warning: The crazies are getting crazier.

Behold the new depth to which macho car culture, blatant anti-environmentalism, and Obama hating has sunk. “Coal rollers” retrofit their pickup trucks to “trick” the diesel engines into thinking they need more gas. The result: big, billowing plumes of black smoke — the better to spew at Priuses and pedestrians.

And that’s precisely the point. These coal rollers take fuel-efficient cars and people hoofing it to be agents of Barack Obama himself, and they delight at engulfing them in toxic smoke. And bicyclists? Don’t get them started.

Voactiv exposed this trend to the non-coal-rolling world last month, quoting people like 25-year-old Robbie from South Carolina, who says rollin’ coal is “just fun… Just driving and blowing smoke and having a good time.”

“I’m not a scientist,” Robbie says, “but it couldn’t be too horrible.”

No, not too horrible — just 21,000 premature deaths each year and a cancer risk that is seven times greater than the combined risk of all 181 other air pollutants tracked by the EPA. That’s what the Clean Air Task Force says about diesel. And they are scientists.

Adding a smokestack to make your man machine even manlier (manliness being measured in toxic smoke, remember) will set you back anywhere from $500 to $5,000, depending, I suppose, on how manly you need to make it. And then there’s all the extra gas you’ll be pumping into your rig. But it’s totally worth it, if you hate Obama and the planet enough.

“I run into a lot of people that really don’t like Obama at all,” one seller of stack kits from Wisconsin told Slate’s David Weigel. “If he’s into the environment, if he’s into this or that, we’re not. I hear a lot of that. To get a single stack on my truck — that’s my way of giving them the finger. You want clean air and a tiny carbon footprint? Well, screw you.”

The EPA says coal rolling is illegal. The Clean Air Act prohibits tampering with an emission control device. And purposely suffocating people in a black cloud of poisonous smoke has to be a form of assault. But breaking those laws must just make coal rolling extra delicious to its practitioners.

According to Weigel, it’s a “use-it-before-liberals-ban-it instinct,” akin to the anti-Earth Hour campaign to keep all the lights on, or the anti-Michelle Obama campaign to eat lots of doughnuts.