One craft idea begets another. After making my footprint alien, I realized that a puzzle piece would make a great alien, too. Affiliate links below.
Puzzle Piece Alien
Prepare the puzzle piece by painting a coat of gesso on the glossy surface. Use a stiff brush or an old toothbrush to make a starry background on black cardstock, as described in the footprint alien project.
When the gesso has dried, paint the alien. I'm a fan of green aliens, but you can obviously choose whatever you want.
When the paint has dried, cut a piece of Twisteezwire and wrap it around the base of a tab, twisting to secure it. (Did you know they're called tabs? Check out this interesting article.) Then twist the ends of the wire around the paintbrush handle, one at a time, to create the curl. Glue a googly eye in place. Cut out a friendly mouth and glue it beneath the eye. (Or whatever. It's your alien. If there's ever a place where there's no right or wrong way to do something, it's when you're making an alien craft.)
Cut out a planet for your alien to sit on and glue it to the starry background. Then glue your alien in place.
There are so many creative possibilities with this project. Give it a try!