Bind Familiar

You gain the service of a familiar. However, unlike the average familiar, this spirit doesn't come to you with its own form. Instead you provide it a corpse and bind the spirit to that form. 

You may bind the spirit to the corpse of any small creature that has perished within the last 24 hours. You place the gem upon the corpse and cast the spell, binding the familiar spirit to it. 

The dead creature must have left behind an actual corpse, thus creatures like fiends, elementals, and incorporeal creatures may not be used. Neither may the corpse be humanoid, unless it was a corporeal undead such as a zombie or ghoul. Non-functional constructs may be used. The binding is not powerful enough to resist a successful casting of spells that return the corpse to life, such as Raise Dead or Resurrection. Familiars will not try to avoid these spells. A bound familiar retains any vulnerabilities, resistances, immunities, and movement types of the creature the corpse had before death. This familiar may not attack, even if another ability would normally allow a familiar to attack. If the bound creature normally creates other creatures, the familiar cannot do so. The familiar does not retain any abilities that can damage other creatures, target non-allied creatures, or cause non-allied creatures to make saving throws. 

Your familiar will behave just as a familiar acquired by casting Find Familiar, and is otherwise the same. See below.

Your familiar acts independently of you, but it always obeys your commands. In combat, it rolls its own initiative and acts on its own turn. A familiar can't attack, but it can take other actions as normal.

When the familiar drops to 0 hit points, its corpse (or other physical form) is destroyed and may not be re-used for this spell..You can dismiss it forever as an action, which also destroys the physical form, making unable to be re-used. It will return if you cast this spell again on a different corpse or other physical form. Being bound to a physical body on the current plane, you cannot temporarily dismiss the familiar to a pocket dimension as with a normal familiar. Whenever the familiar drops to 0 hit points or is dismissed it leaves behind in its space anything it was wearing or carrying.

While your familiar is within 100 feet of you, you can communicate with it telepathically. Additionally, as an action, you can see through your familiar's eyes and hear what it hears until the start of your next turn, gaining the benefits of any special senses that the familiar has. During this time, you are deaf and blind with regard to your own senses.

You can't have more than one familiar at a time. If you cast this spell while you already have a familiar, you instead bind it to a new form. Finally, when you cast a spell with a range of touch, your familiar can deliver the spell as if it had cast the spell. Your familiar must be within 100 feet of you, and it must use its reaction to deliver the spell when you cast it. If the spell requires an attack roll, you use your attack modifier for the roll.