Mutant Crystal-fur Mouse

There is a region, right along the road, where it is possible to hit these mobs with long-range attacks BUT still be outside the legal range for these mobs to move. In this case they will ignore your attacks or, if you moved outside that range after attacking them, they will break.
It is possible to surf this boundary to more safely fight these, but the boundary is not marked in any way. You just have to learn it.