You can shave with this.
This is a weapon quite unlike all the others.
The Battle Axe is a close combat weapon, it splits your enemies health in two and buries the Worm in the landscape.
If the Worms' health is down to a single point then the Battle Axe will kill them.
The Battle Axe is of course most effective on those Worms with a lot of health. Work out whether or not the Battle Axe would do more damage than your most powerful weapon would before using it, and look out for enemies Worms grouped together in more than one place.