Hit Dice [d10s] equal to the level of the spell
Challenge — Proficiency Bonus equals your bonus
Damage Resistances (Chromatic and Metallic Only) acid, cold, fire, lightning, poison
Damage Resistances (Gem Only) force, necrotic, psychic, radiant, thunder
Shared Resistances. When you summon the dragon, choose one of its damage resistances. You have resistance to the chosen damage type until the spell ends.
Multiattack. The dragon makes a number of Rend attacks equal to half the spell’s level (rounded down), and it uses Breath Weapon.
Rend. Melee Weapon Attack: your spell attack modifier to hit, reach 10 ft., one target. Hit: 1d6 + 4 + the spell’s level piercing damage.
Breath Weapon. The dragon exhales destructive energy in a 30-foot cone. Each creature in that area must make a Dexterity saving throw against your spell save DC. A creature takes 2d6 damage of a type this dragon has resistance to (your choice) on a failed save, or half as much damage on a successful one.