Alien: Assembly Required is a game on the Arthur page of the PBS Kids website.
Buster is lying in bed, staring at the blinking light on the smoke detector on his ceiling. He imagines it is a Flying Saucer that lands in his backyard.
"Drag and drop alien parts from the left screen to the right screen. Drag a part to the recycle bin to get rid of it. Click RANDOM to get a pre-built alien that you can edit. Click START OVER to clear your alien and build a new one. When you've built the alien of your dreams, click DONE."
When you are done, the flying saucer takes Buster to Planet X, Milky Way, which is a planet inhabited by the alien you have designed. A newspaper ("The Daily Alien") appears - featuring Buster and the Supreme Ambassador alien - which you can print so you can save your alien.
Arthur's glasses and Buster's ears are included with the 'odd bits' alien parts.