A freakish little monster called a tardigrade (or water bear) can survive in space. Scientists found this out by shooting them out into orbit, collecting them again, and watching them mate. Weird way to pay the bills.
"They have claws and eyes. They are real animals. And this is the first time such an animal was tested in space," said Petra Rettberg, an Institute of Aerospace Medicine microbiologist.
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Vacuum (imposing extreme dehydration) and solar/galactic cosmic radiation prevent survival of most organisms in space. Only anhydrobiotic organisms, which have evolved adaptations to survive more or less complete desiccation, have a potential to survive space vacuum, and few organisms can stand the unfiltered solar radiation in space. Tardigrades, commonly known as water bears, are among the most desiccation- and radiation-tolerant animals and have been shown to survive extreme levels of ionizing radiation. Here, we show that tardigrades are also able to survive space vacuum without loss in survival, and that some specimens even recovered after combined exposure to space vacuum and solar radiation. These results add the first animal to the exclusive and short list of organisms that have survived such exposure.
inevitable conspiracy theory
this little incredibly tough, adaptive and survival-oriented critter could have ridden to the Earth as a full adult in its Tun form (not just as an egg) in any space-traveling body (comet, asteroid, etc.) that could have survived to impact the Earth's surface. In other words, it is clearly within the realm of possibility that this creature may not even be originally native to Earth.
The fun part of the conspiracy theory web page is I actually discovered it after describing it.