A portal turret with a 3mm red LED and a CR2032 battery.
The design is a little too complicated to print nicely, so maybe later I will make an alteration to it.
Step1: print the 3D model
Step 2: clean the print support
Step 3: hotglue the LED in place
Step 4: hotglue the 2 models together
Step 5: Insert battery in the back, and enjoy the glow :)