The Trouble With Humans

Humans-there's no understanding them, and no dealing with them either. Or even their planet. Pity the poor aliens, whose shape-changing ability should let them take over the planet Earth before the humans even know they're there-if it weren'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 seasons is hardly noticeable.