Inflatable Hedgehog or Zamba Zaraa is a creature, reported from the Gobi Desert of Mongolia. It is described as looking something like a hedgehog. When threatened, the animal strikes its tail against the ground (an alarm action that is used by many different types of animal) and then proceeds to inflate itself considerably. Reports differ on how big it is after inflation, and range up to the size of a yurt (a small Mongolian tent-like dwelling).
There are other creatures who inflate themselves as a defense mechanism, most notably puffer fish. It would be weird, but not impossible, for a mammal to have evolved the same trick. Since the Gobi Desert is one of the least-explored areas on earth, it is plausible that it contains many new species that are just waiting to be discovered. Perhaps the inflatable hedgehog is one of these undiscovered animals, and someday we will be able to see it in zoos.