At gun stores from coast to coast, and on the Internet, they are known as "exploding targets."
But the man who oversees Maryland's bomb squad has another name for them: Explosive Kits for Dummies.
Amazingly simple to assemble -- just pour two powders into one container and shake -- the targets are a safe and fun way to enhance target shooting, manufacturers say.
Shoot it with a bullet from a safe distance, and you'll be rewarded with a concussive blast and a cloud of smoke, indicating you've hit your target.
But if you search YouTube for "Tannerite" -- the most popular brand -- and you'll find more than 100,000 videos depicting the use -- and more frequently, the misuse -- of the product.
Online videos show people in a veritable contest to see who can detonate the most explosives in the most innovative way, demolishing pumpkins and watermelons, dead cows and pigs, washing machines and refrigerators, old cars and trucks, Elmo dolls and even a trailer home.
To heighten the impact, diehards mixed it with gasoline, diesel fuel or propane tanks, creating explosions that crater the land, trigger car alarms, and shaking nearby communities.
In one video that is now an Internet staple, a Minnesota man in 2008 detonated 100 pounds of Tannerite in the dump box of an old dump truck, sending the truck aloft -- while rattling a nearby nuclear power plant and, inconveniently, the police department.
The nuclear plant went into a short lockdown and the man later pleaded guilty to two felonies involving explosives.
Last year, Maryland became the first state to regulate exploding targets, requiring users to be trained and licensed to handle explosives. Some California jurisdictions have also interpreted state law to restrict use of the targets.
And last month, exploding targets got even more notoriety when the U.S. Forest Service banned the targets on its property in five western states (Colorado, Wyoming, South Dakota, Nebraska and Kansas) saying the targets ignited 16 fires on Forest Service lands coast-to-coast since January 2012. The cost of extinguishing those fires: more than $33 million.
Forest Service officials say they hope to extend the year-long ban, and extend it nationwide.
And in March, the FBI distributed a bulletin to law enforcement agencies nationwide warning that exploding targets could be used "as an explosive for illicit purposes by criminals and extremists" and its components could be used to make IEDs.
One state's decision
Maryland Chief Deputy State Fire Marshal Joseph Flanagan said he fought to regulate exploding targets after the product appeared on local gun store shelves.
Gun stores were giving Maryland residents a "false sense that it was OK to use," he said, even though customers unknowingly broke Maryland law preventing them from "manufacturing" explosives whenever they combined the targets' two ingredients.
So Flangan pushed a bill to expand the definition of explosive to include "two or more components" when packaged together that create a bomb.
The bill failed on its first two attempts, but passed in 2012 after a representative from the National Rifle Association signed a letter saying the NRA was taking "no position" on the bill.
Gun rights advocates did not oppose the measure "because there are so many other things that are more important to us, and it doesn't really involve guns," said John H. Josselyn, legislative vice president of Associated Gun Clubs of Baltimore. "We looked at it, considered the impact on our members and wrote it off as another feel-good issue by the left wing that has nothing better to do."
Josselyn said he remains "philosophically" opposed to the restrictions since "we banned one more thing that wasn't causing a problem."
Flanagan acknowledges that exploding targets had not caused many problems in Maryland. But, he said, as the products began appearing on local store shelves, Maryland wanted to be in front of the problem.
"This is a high explosive and it belongs in the category with other high explosives," Flanagan said. "We're not going to wait for an incident to occur where this product is used, where it's just purchased off the shelf. We are not sorry for the action we took."
Fire marshals from several other states have sought Maryland's guidance as they contemplate similar regulations, he said.
In Indiana this year, self-described "very pro-gun" Republican state senator Jim Merritt introduced a bill to require retailers to place Tannerite in locked displays, and to require that purchasers to be at least 18. There are currently no age limits on its purchase.
The bill died under the weight of legislative business, Merritt told CNN, although he may introduce it again.