Raid your recycling bin and scare up a cast of extraterrestrial characters.
Fill your bottles with plastic beads, pennies, pinto beans, or colored sand.
For the head, use a craft knife (adults only) to cut a hole in a small ball (a mini sponge ball or foam football) large enough to fit over the cap of the bottle body it goes with. Pull the out a small amount of the inner foam once you cut the opening.
Add the facial features with acrylic paints, or use tacky glue to attatch bottle-cap or button eyes. For a bug-eyed effect, try cutting a mini ball in half.
For hair, make holes in the ball and insert golf tees or plastic forks ( you may need to trim the fork handles to half their length first).
Add ears by partially inserting plastic milk jug caps into slits cut into the sides of the ball.
For arms, curl colored craft wire (or a pipe cleaner) around a pencil. Then use a strip of packing or duct tape to attatch the center of the curled wire to the back of the bottle.
Cut out hands from craft foam or felt, and glue or tape them to the ends of the wire.