Unfamilar

You transform the corpse or skeleton of a CR 0 Tiny beast within range into an undead pet, an unfamiliar. It uses the beast's game statistics, but its creature type becomes undead and it no longer requires air, food, drink, or sleep.

Your unfamiliar acts independently of you, but always obeys your commands. In combat, it rolls its own initiative and acts on its own turn. It can take any action that its beast form was capable of, including attacks.

While your unfamiliar is within 100 feet of you, you can command it telepathically. Once given an order, your unfamiliar continues to follow it until its task is complete.

When your unfamiliar drops to O hit points, it dies, but its corpse can be targeted again by this spell unless your unfamiliar was killed by fire damage, radiant damage, or a critical hit. When you target the corpse of an unfamiliar you have already created with this spell, you can ignore this spell's material component requirement.

You can't have more than one unfamiliar at a time. If you cast this spell while you already have an unfamiliar, the previous one dies instantly, as the necromantic energies animating it are transferred to your new unfamiliar.