Bushalo

The Bushalo of Mars can't be really described in words (the picture is far better suited for this). It wanders over the surface of the planet in big herds and normally is a peaceful plant-eater (although this his a totally different meaning on Mars!). However, once provoked, the Bushalo will turn into a living battering ram, waltzing through everything in its way.

So don't provoke it.

Lore
''The plains areas are home to this bison- or buffalo-like herbivore. Herds of bushalo can generally be found near the wandering forests. feasting on the small plants found in and around the woods. Though normally sedate, these massive, hippopotamus-sized creatures are easily provoked. The charge of a bushal, wood-like tusks clacking, is something to behold from a distance. The best advice that can be given is to leave these creatures alone unless it is absolutely necessary to disturb them.''

- from "Mysteries of the Red Planet", Martian Dreams