Adamantine Punch Knife

Sap (Mastery): If you hit a creature with this weapon, that creature has Disadvantage on its next attack roll before the start of your next turn.

Whenever you hit an object with this weapon, the hit is a critical hit.

Proficiency: simple, punch knife Source: Xanathar's Guide to Everything p. 78, Ben Huffman - Pugilist (Third Party)