M72 LAW. I've actually shot a live one during my mandatory time at the military as a practice shot (We destroy our aging stock by making conscripts shoot them as a training exercise).

As a weapon it's the typical shaped charge warhead. It would be really dangerous against any normal non tank vehicle in short ranges. Against a tank it's useless nowadays. But the semi militarized armored cars used by some police forces would be disabled rather easily with one. Not blown up to smithereens, but a hit to the engine space would wreck that or a hit to the passenger compartment would kill some if not all inside.

Not that good against a building. A hand-grenade would do way more harm inside. So it's more of a trophy thing, or a really nasty surprise against SWAT truck assuming the culprit manages to hit with it.

The lax security Australia has towards these is rather hilarious.