Hobby drones. Unmanned aerial vehicles. Remote-controlled copters.
Call them what you will, they're becoming a nuisance.
A minority of irresponsible users has been flying them too close to aeroplanes and helicopters; wandering into restricted military airspace; spying on neighbours; disrupting sporting events; and even injuring people.
It was only a matter of time before some trigger-happy vigilante shot one of the pesky privacy invaders out of the sky.
Regulators and law enforcers are struggling to cope with the growth in their popularity, increasing the likelihood that heavy-handed legislation could stifle innovation in a sector that has great commercial potential for businesses large and small.
"This is a very hot topic," said Gary Clayton, chair of the Unmanned Aerial Vehicle Systems Association, a trade body representing several hundred commercial drone users.