Cover CDs with Duck Tape. We used solid colors for two of ours and a rainbow patterned tape for the third.
Cut triangle shapes from contrasting tape (for solid tape CDs, use a patterned tape for the triangles and vice versa). Tape them around the sides of the CD.
For mouths and teeth, cut a piece of white tape in a rectangle and stick to the front of the CD. Use a black marker to add lines and a outline around the teeth. For single teeth, cut a small rectangle or triangles and stick to the CD. Use a black marker to trace around to add an outline and to also add a line for the mouth.
For a large eye, cut a piece of white tape about 4 inches long. Fold it in half and stick it to itself. Cut a circle from the tape. Do the same with black tape, only cut the circle smaller. Glue the black circle to the white circle, then glue the eye to the CD.
Use glue to attach googly eyes to the other CD monsters.