A charming Martian with evocative alien eyes and robes, and a classic flying saucer to travel around in. Both models are fully 3-D, and fairly quick and easy to fold.
Wise Martian is unpublished, Flying Saucer appears in Air and Space Origami by John Szinger.
Both models can be folded nicely from 6" (15cm) paper. Kami, foil, Tant, etc., all work well.