The flail is a medieval weapon, made of (one or more) weight(s) attached to a handle with a hinge, rope, or short chain. They originated from farming flails, which were used to thresh grain.
A rule of thumb, if the weapon has a chain over an arm's length (and more so over 1.5 arm's lengths), then the weapon is most likely a ball and chain instead.
This tag implicates weapon (learn more).