What creatures live on Mars?
If anything it would be the most basic one cell creatures. Mars would only have had a 10-100 million year (thats earth years) window in which life could have formed on its surface. Compared to the Billion years earth had to brew its first microbial lifeforms, that is a very narrow window of opportunity making it improbably (but not impossible) for life to form there. Although there was a short cartoon film I remember that made me laugh where the surface of mars is littered with rovers and probes, and these aliens poke their heads out from under this rock and examine the latest rover to land near their hole. Then decide to leave it alone and go back underground.
No physical creatures live on mars but it is where all the souls of astronomers go as well as geeky nerds that like playing alien type computer games. Although the surface of the planet may appear bare ectoplasmically speaking it is littered with giant telescopes, computers and those 1980s space invaders games.
