Ancient Firespike Dragon

Lesser Legendary Resistance (2/Day). If the dragon fails a saving throw, it can choose to reroll it with advantage.

Multiattack. The dragon may use its Lesser Frightful Prescence. It then makes one bite attack and two claw attacks.

Bite. Melee Weapon Attack: +8 to hit, reach 15 ft., one target. Hit: 12 (2d6 + 5) piercing damage plus 3 (1d6) fire damage.

Claw. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 9 (1d8 + 5) slashing damage.

Tail. Melee Weapon Attack: +8 to hit, reach 15 ft., one target. Hit: 11 (1d12 + 5) bludgeoning damage.

Lesser Frightful Presence. Each creature of the dragon's choice that is within 90 feet of the dragon and aware of it must succeed on a DC 13 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the dragon's Frightful Presence for the next 24 hours.

Fire Breath (Recharge 5–6). The dragon exhales fire in a 70-foot cone. Each creature in that area must make a DC 15 Dexterity saving throw, taking 45 (13d6) fire damage on a failed save, or half as much damage on a successful one.

Explosive Shield (Recharge 5-6). The dragon creates a magical shield around itself that lasts until the end of the next round. While the shield is active, damage the dragon takes from attacks and the results of failed saving throws is reduced by 17 (5d6). Once the shield has reduced a total of 42 (12d6) hit points worth of damage, it explodes in a 40-foot radius. When the shield explodes, each creature hostile to the dragon and its allies within the area must make a DC 16 Dexterity saving throw, taking 9 (2d8) force damage and being knocked prone on a failed save, or half as much damage and no other effects on a success.

Rejuvenating Heal (Recharge 4-6). The dragon channels magical energy and heat through its body, causing it to regain 4d8 hit points at the start of each of its turns for 1 minute.

The dragon can take 2 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. The dragon regains spent legendary actions at the start of its turn.

Detect. The dragon makes a Wisdom (Perception) check, with advantage if the dragon and/or what it is perceiving is in a fiery or cavernous environment.

Tail Attack. The dragon makes a tail attack.

Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 10 feet of the dragon must succeed on a DC 15 Dexterity saving throw or take 11 (1d12 + 5) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.