Way back in the day, post Jurassic Park: The Lost World, there was a toy that was essentially rock'em sock'em robots, except with FUCKING VELOCIRAPTORS.
The toy was basically a raptor on a long handle attached to his foot, he had a button on his chest that ejected him, and there was a knob at the end of the handle you used to spin the raptor and make his limbs flail. They also roared, snarled, hissed, etc.
They roared, snarled, and hissed randomly inside the garage boxes against the wall of my bedroom. Took us weeks to figure it out.
Also furby with low battery = nightmare fuel when from the depths of the closet you hear "Oooooh waaah... Daaaark.." In the deepest slowest voice one could imagine. That furby went away quite soon.