He has appeared in many myths and legends throughout the Galaxy, and it is unknown what species (or gender) it really is.
He has never been observed for long and has never been caught. He doesn't even speak, he only either giggles or growls. His face also seems to be permenantly fixed into a snarling expression.
Many legends and myths involve this strange creature, and to this day no-one knows where he comes from or what species he is. Many have speculated that he might be a ghost, some kind of alien, a mutant or even some kind of genetic experiment that went wrong. Whatever his origins, this guy is a serious weirdo.