sure...
you'll need some clear resin, silicon mold, some blue resin dye, cr2032 battery and holder, blue LED
*make a square mold
*cast a clear resin cube w/ some blue color added in.
*after cured, drill out a hole the diameter and the depth of your led so it will sit flush on the bottom of the cube. i used a blue led so the voltage is perfect for a cr2032 battery (3V).
*sand the outside surface of the cube w some 220 to dull the entire thing. (the tesseract was never crystal clear like the one included with the figure)
*attach the power source and switch under the coat to his leg and run the led and wire up and out his sleeve.
*attach the led to the cube (i use a tiny piece of stick tack) and place the cube in his hand.
*tweak everything right and you'll never see the wire and electronics are hidden under his coat and never seen as well.
*go drink some captain and marvel at the skull!