My first idea for Halloween outfit is the devil mask, there are some scars on its surface, and the eyes I will use LED to change the brightness.
My second idea is wearing the mask and have one light sword which can change the color. But I still figuring out where to put the circuits things is better.
The third idea is the robot BB8, and I will make a robot shape and put the LED inside its eyes, and change the color. And when I wear on it, it can rotate the head side, so make it more like a real robot.