Dragon's Polymorph

This spell transforms you into the form of any Beast (including Half-Dragon Beasts) whose challenge rating is equal to or less than your level. Your game statistics are replaced by the stat block of the chosen Beast, but the target retains its alignment, personality, creature type, Hit Points, and Hit Point Dice. You gain a number of Temporary Hit Points equal to the Hit Points of the new form. The spell ends early if you have no Temporary Hit Points left.

You are limited in the actions you can perform by the anatomy of your new form, and it can’t speak or cast spells. Your gear melds into the new form. You can’t use or otherwise benefit from any of that equipment.

If you choose a half-dragon beast form, you gain the following features:

Senses. You gain blindsight with a radius of 10 feet and darkvision with a radius of 60 feet.

Resistances. You gain resistance to a type of damage based on the color of the draconic blood used to cast the spell. If sourced from a non-chromatic or non-metallic creature such as a Dragon Turtle or Wyvern, roll a d20 and consult the table below to determine the color used for the duration of the spell.

Breath Weapon (Recharge 5-6). Your half-dragon form has the breath weapon of its dragon half. Your new size and CR determines the damage.

Prerequisites:
CR 2 & Large or smaller: As Wyrmling
CR 7 & Huge: As Young Dragon
CR 8 & Gargantuan: As Adult Dragon

If you use your Breath Weapon, roll a D6 at the beginning of your next turn. If you roll a 5 or 6, you may use your Breath Weapon again. If not, you may roll again at the beginning of your following turns.