Trouble With Humans

Humans-there's no understanding them, and no dealing with them either. Oreven their planet. Pity the poor aliens, whose shape-changing ability should letthem take over the planet Earth before the humans even know they're there-if itweren't for all that omnipresent pollution. Or consider another set of invaders,from a planet where the weather is always mild and the changing of the seasonsis hardly noticeable.