The Apocra Security Defense Android (or ASDA) is an afforable solution for intelligent, masterful and loyal safeguarding of locations and personnel.
The standard model comes equipped with a long range high energy lightning gun for incapacitating or neutralizing both organic and inorganic targets. If you require something more heavy duty, both arms can be easily replaced with other compatible weaponry and tools.

I made another iteration of this a long while back, though I really like how this turned out.