Shapechanger

10th Level School of Transmutation

At 10th level, you add the Polymorph spell to your spellbook, if it is not there already. You can cast Polymorph without expending a spell slot. When you do so, you can target only yourself and transform into a beast whose challenge rating is 1 or lower.   Once you cast Polymorph in this way, you can’t do so again until you finish a short or long rest, though you can still cast it normally using an available spell slot.