The robot helmet/mask is made of common parts found at a hardware store....a cheap grinder faceshield, a bucket, and cardboard.
The electronic parts are hobby store type parts,: an Arduino Nano, WS2812 strips, a LipO battery, 2 gearmotors, 2 DC buck power supplies., a pushbutton.

 

The type of scanning LED eyes on the robot are selected by pushbutton: cylon red, cylon blue, cylon green on white, police lights mode, flux capacitor mode, etc...
maybe not totally scary by itself, but with a robot voice modulator, and a repulsor ray, better not venture too far out in space