Immutable Form. The Dragon is immune to any spell or effect that would alter its form.
Legendary Resistance (3/day). If the dragon fails a saving throw, it can choose to succeed instead.
Self Destruct. When the dragon is reduced to 0 hit points, it explodes, and each creature within 30 feet of it must make a DC 18 Dex Saving Throw, taking 21 (6d6) fire damage and 21 (6d6) piercing damage on a failed save or half as much damage on a successful one.
, +4 to hit with spell attacks). The acolyte has following cleric spells prepared:
Cantrips (at will): light
Multiattack. The dragon makes three attachs: one with its bite and two wth its claws.,, one target.
Hit: 2 (1d4) bludgeoning damage.