Flooze

The versatility of the magically-enhanced ooze used to craft this flail can't be overstated. Its high tensile strength allows its 'chain' to stretch in response to its wearer's thoughts, while the flail's head boasts a hardness and density comparable to steel. This magic flail deals an extra 1d6 acid damage to the first target it hits on each of your turns. The flail has 8 charges and regains 1d4 + 4 expended charges daily at dawn.

Reachier. While holding the flail, you can expend up to 4 charges (no action required) to increase your reach with this weapon by 5 feet for each charge expended until the end of your turn.

Proficiency: martial, flail Source: Heliana's Guide to Monster Hunting - Part One p. 439, Player's Handbook (2014) p. 149