Flail Expert Feat

Your mastery with a flail allows you to use the challenging weapon with deadly skill. You gain the following benefits while wielding a flail:

Prerequisite: Proficiency with flails

• Dangerous Swings. When you miss a melee weapon attack made with a flail, ou can make a new attack roll against another creature you of your choice within the weapon’s range. You cannot attack the same creature twice this way.
• Wind Up. As a bonus action, you can whirl the flail building momentum. The nxt attack you make with it before the end of your turns an additional 1d8 damage on hit.

Source: KCLL, page 186