ha ha! fooled ya!
easy peasy lemon squeesy gag item
Buy whiteout at the dollar store.
Dump some out on wax paper, let the rest spill naturally as it lays down. (make it as flat and straight as you can or there'll be shadows and wrinkles).
Let dry for a long time. Have fun.
Try with nail polish. Reinforce the bottom with some thin cardboard is you like.