Military one-handed melee weapon
Cost: 10 gp
Damage: 1d10
Proficient: +2
Weight: 5 lb.

Based on a simple agricultural tool, a flail is a wooden handle attached by a short chain to a spiked metal ball. The chain allows a skilled warrior to generate impressive force with each stroke or entangle a foe’s legs or arms.

Versatile (Versatile weapons are one-handed, but you can use them two-handed. If you do, you deal an extra 1 point of damage when you roll damage for the weapon.
A Small character such as a halfling must use a versatile weapon two-handed, and doesn’t deal extra damage.

Flail (Weapons in the flail group have a flexible material, usually a length of chain, between a solid handle and the damage-dealing end of the weapon.).

Published in Player's Handbook, page(s) 218, Mordenkainen's Magnificent Emporium, page(s) 21.