Maybe they've been watching Monty Python's the Quest for the Holy Grail and figure that the mouse is the closest thing to the furry monster in the movie so they're taking their vengeance upon it early before it can start wrecking untold havoc on the masses!

You should be thankful and shower them with praise!





Or, they could be bots testing out script patterns on a random monster that's high enough in level to not die instantly, but not so terrible that they have to really worry about being killed by it.

But probably the holy grail thing.