Rover...
"The "Tumbleweed" air vehicle, for instance, is a multi-rotor hovering electro-copter with a difference. The final version will have a spherical structure, enabling it to "roll along the ground and even up walls," according to its Manchester Uni designers, and "perch and stare from suitable urban structures". The tumbling ball-copter should be able to fit through doors, and have a price tag such that losing a few would be no problem."
anyone else think this sounds like the giant white ball "robot" from "The prisoner" (AKA "Rover")? all it needs is to be able to latch onto and suffocate/electroshock fleshy targets!