Exotic Familiar

You gain the service of an exotic familiar, a spirit that takes an exotic form you choose: Any small unaligned monstrosity or beast with a CR above 0. Appearing in an unoccupied space within range, the familiar has the statistics of the chosen form, though it is a celestial, fey, or fiend (your choice) instead of a monstrosity or beast.

Your familiar acts independently of you, but it always obeys your commands. In combat, you and it roll the same initiative and it acts on its own turn. A familiar can attack, and it can take other actions as normal.

When the familiar drops to 0 hit points, it disappears, leaving behind no physical form. It reappears after you cast this spell again. As an action, you can temporarily dismiss the familiar to a pocket dimension. As an action, while it is temporarily dismissed, you can cause it to reappear in any unoccupied space within 30 feet of you. Whenever the familiar drops to 0 hit points or disappears into the pocket dimension, it leaves behind in its space anything it was wearing or carrying.

You can't have more than one familiar at a time. If you cast this spell while you already have a familiar, you instead cause it to adopt a new form. Choose one of the forms applicable for this creature. Your familiar transforms into the chosen creature.

Finally, our familiar deals +15 radiant damage if a celestial, +15 poison damage if a fey, +15 acid damage if an elemental, or +15 fire damage if a fiend on each of its attacks.

If your character level is 5 or higher, you can make the creature's size only Small or Tiny, and the creature can have a CR of 1/2 or lower, but still above 0.