Naw, it rains strange crap all the time. Well, maybe not all the time, but it's not as rare as you might think. I read a Bathroom Reader article on it. It has, at various times, rained frogs, tadpoles, fish(!), funny globules, pretty much anything weird you can imagine.
Wikipedia has some info an animals comming from the sky. There are theories as to why it happens, but none of them are really all that backed by evidence.
The common theme, though, is that the objects are generally water born. Things that exist in pools of water. How they got into the air is a mystery, but they're definately related to water. If it was extraterrestrial in origin, why would it be limited to very familiar, terrestrial marine organisms? Why not rains of mice or jaguars? Why are the organisms which fall so readily identifiable as terrestrial. I find the idea of extra terrestrial organisms raining down on Earth highly dubious, but not impossible.
It would rather change the predominant view of evolution, speciation, and life origin wouldn't it? Strong Panspermia would need to be re-evaluated.
