You can get a trial version of Spore’s Creature Creator. It only gives you 25% of the available options, but I still managed to make anything I wanted. Including this Cyclops Monkey Deer.
It’s pretty easy to make animals inspired by Earth animals, but I had a really hard time making alien creatures. Not because Spore won’t let you, because the left side of my brain wouldn’t shut up. It kept explaining that there was no way a 6 legged pink Elephant with flippers and a spike on its tail could survive. Or it’d tell me there’s no point to those mosquito wings when placed on a large bovine animal.