To give a spooky edge to a lampshade black cardstock is your best friend. It's amazing how many strange things you can find on google images! I just googled mice silhouette and bam...there you have these little guys just begging to make a lampshade their home. I printed them on regular printer paper, cut them out and traced them onto black card stock then cut that out. A little tape and that's it! You can see them when the lights off but at night they really light up well! I think bats would be great too!