Mindblade

This item appears to be a dagger hilt. While grasping the hilt, you can use a bonus action to cause a blade of purple flames to spring into existence, or make the blade disappear.

You gain a +2 bonus to attack and damage rolls made with this weapon, which deals psychic damage instead of piercing damage. When a fey, giant, or humanoid creature is slain using this weapon, for the next 1d4+2 days the resulting corpse can be possessed (such as by magic jar or a ghost ) as though it were still alive.

Alternatively, during that time you may expend a charge to use the dagger to animate the corpse as animate dead with a casting time of 1 action. You must reassert your control over the undead creature within 24 hours using 1 charge, or it ceases obeying any commands. Casting the animate dead spell on such a creature has no effect. Regardless, it reverts to a corpse when the allotted time is up and cannot be reanimated in this way again. The dagger has 4 charges and regains 1d4 expended charges each dawn.