Animosity

A steel black bat (baseball bat), that has the word animosity carved into it on the pommel of the bat as well as a persistent bloodstain on the top end of the bat that doesn't seem to be able to be removed, the grip is made of leather that is from an unrecognizable animal and some might actually think it's from a humanoid

You gain a +1 bonus to attack and damage rolls made with this weapon

This weapon uses a d8 for damage and can be used with two hands for a d10 with the versatile property

Animosity: when you are damaged while attuned to this weapon, you use a d10 (d12 versatile) instead of the normal d8 (d10 versatile) when hitting the target that caused you damage, this applies to all creatures that do damage to you. This also negates any disadvantages given by targeting the specific enemy, additionally, when you score a crit with this weapon while attuned you can make an additional weapon attack on that turn for free (this can only be used once per round)

curse: however you must make a wisdom save every time you take damage, on a success nothing happens, on a fail you may only act against enemies that have done damage to you (if none have, say for poisoned food, then you attack the nearest creature that you dislike the most)

Proficiency with a Club allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: You must kill a creature with this weapon to be able to attune to it. It takes 10 straight minutes of conecentrating on violent thoughts that the weapon feeds you while you attune to it. You canno't unattune to this weapon unless you are killed, or the remove curse spell is used on it, Light, Slow