The background image suggests that you should bend down (or throw yourself on the ground) to evade taking a hit from mace-flail thing.
It's not a 'mace-flail thing', it's a peasant's flail, derived from an agricultural tool used for threshing. There's also a shorter type of flail with a ball at the end rather than a cylinder, which is what you might have been thinking of, and that is built entirely for combat, rather than being repurposed.