Clockwork Manticore

Lightning Absorption. Whenever the manticore is subjected to lightning damage, it takes no damage and instead regains a number of hit points equal to the lightning damage dealt.

Immutable Form. The manticore is immune to any spell or effect that would alter its form.

Magic Resistance. The manticore has advantage on saving throws against spells and other magical effects.

Multiattack. The manticore makes three attacks: one with its bite and two with its claws or one tail attack followed by two tail blasts.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3) piercing damage.

Claw. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) slashing damage.

Tail Grab: Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 8 (1d8 + 4) bludgeoning damage. Target must succeed a DC 15 Strength saving throw to pry their way out of the tail. On a fail, the target is grappled, taking 5 bludgeoning damage each round. Grappled targets absorb all Tail Blast attack damage.

Lightning Tail Blast. The manticore exhales lightning in a 30-­foot line that is 5 feet wide. Each creature in that line must make a DC 12 Dexterity saving throw, taking 22 (4d10) lightning damage on a failed save, or half as much damage on a successful one. Creatures with metal parts or armor have disadvantage on this saving throw. If a creature is grappled by the tail, this attack is automatically considered a critical hit. Grappled creatures can then attempt to escape the grapple.