Well... Hercules kills some mythical animals. I. E. a lion. with his bare hands. And wears the lion's head (which suddenly is much smaller.... O.o ). Buuuuut the animals are clearly CGI.
The closest thing to a dragon is the Hydra (a dragon-like creature with multiple heads) which was said to have been slain by Hercules, However it is strongly implied to have not been real and was in reality warriors wearing serpent-masks