The Pentagon's pain ray? Pointless. The laser dazzler? Lousy. The anti-vehicle slippery foam? Washed out.

That's the upshot of a highly critical report released last week by the U.S. Government Accountability Office and expounded upon by Wired News.

The report found that the Department of Defense's Joint Non-Lethal Weapons Program (JNLWP) has spent $386 million since it was formed in 1996, and created exactly zero useful non-lethal weapons.

For example, the Active Denial System (ADS) or "pain ray," which focuses microwaves on a target's skin to create intense pain without any lasting effect, does work, as several journalists found out when it zapped them during demonstrations a couple of years ago.

But it takes 16 hours for it to warm up, according to the GAO report. It weighs 9 tons. It's so complicated it can't be fixed in the field. After spending $55 million, the DoD decided not to deploy it overseas.

But at least the ADS is still being worked on. Two other projects were terminated after a total of $12 million had been spent.

The Mobility Denial System, military-speak for slippery foam that rendered roads impassable, just used too much water while operating. It took 8 years to discover that.

The FN303 Less-Lethal Launching System, a souped-up paintball gun, was heavy and fell apart easily. Nevertheless, it was deployed for a while even though the DoD never figured out how to properly supply the compressed-air canisters the guns needed.

As for laser dazzlers, meant to temporarily blind unruly mobs, the GAO pointed out that those revealed a more systemic problem — some of these "non-lethal" weapons turned out to be pretty damaging overall.

Several GIs had their vision impaired, at least one permanently, when they were accidentally hit by a truck-mounted dazzler.

• Click here for more photos.

• Click here for the GAO report (pdf).

• Click here for the Wired News synopsis.

• Click here for FOXNews.com's Patents and Innovation Center.