Animated Long Dragon Puppet

Dancer. Whenever the puppet makes a dexterity saving throw, it does so with advantage. Additionally, each turn, the puppet must spend at least 20 feet of its movement.

Death Burst. When the puppet dies, it lights on fire, as described below in the Flaming Body trait, and explodes, and each creature within 20 feet of it must make a DC 19 Dexterity saving throw, taking 56 (16d6) fire damage on a failed save, and half as much on a successful one. The explosion ignites flammable objects in that area that aren't being worn or carried and destroys all traces of the puppet. 

Any creatures swallowed by the puppet automatically fail the saving throw, but are automatically freed from the puppet's stomach.

Fire Absorption. Whenever the puppet is subjected to fire damage, it takes no damage and instead regains a number of hit points equal to the fire damage dealt.

Flaming Body. The puppet may use its action to light itself on fire or douse it. Any creature that touches the puppet or hits it with a melee attack while it is aflame must make a DC 19 Dexterity saving throw. On a failure, the creature takes 8 (1d12 + 2) fire damage, taking no damage on a success. 

While aflame, the puppet deals an extra 8 (1d12 + 2) fire damage with its melee attacks and sheds bright light for 10 feet and dim light for an additional 10 feet.

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

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

Magic Weapons. The puppet's weapon attacks are magical.

Multiattack. The puppet makes seven attacks; one with its sear, one with its slam, one with its bite, and four with its claws.

Bite. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 23 (3d10 + 7) piercing damage. 

If the target is a creature and the puppet is aflame, the creature must succeed on a DC 19 Dexterity saving throw or ignite in magical flames. The flames do 8 (1d12 + 2) fire damage each turn. A creature that takes this damage must make a DC 19 Constitution saving throw or have its hit point maximum reduced by an amount equal to the damage taken. The target dies if the fire reduces its hit point maximum to 0. The reduction lasts until removed by the greater restoration spell or other magic.

The flame can only be doused by dealing bludgeoning damage to the creature that is aflame from a magical attack.

Claw. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 20 (3d8 + 7) slashing damage. If the target is a creature and the puppet is aflame, the creature must succeed on a DC 19 Dexterity saving throw or ignite in magical flames. The flames do 8 (1d12 + 2) fire damage each turn. A creature that takes this damage must make a DC 19 Constitution saving throw or have its hit point maximum reduced by an amount equal to the damage taken. The target dies if the fire reduces its hit point maximum to 0. The reduction lasts until removed by the greater restoration spell or other magic.

The flame can only be doused by dealing bludgeoning damage to the creature that is aflame from a magical attack.

Sear. Ranged Weapon Attack: +13 to hit, range 15/60 ft., one target. Hit: 17 (3d6 + 7) fire damage. If the target takes damage from the attack, it must make a DC 19 Dexterity saving throw. Failing the saving throw causes the creature to catch fire; until someone takes an action to douse the fire, the creature takes 8 (1d12 + 2) fire damage at the start of each of its turns. The creature takes no effects on a success.

Slam. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 20 (3d8 + 7) bludgeoning damage. 

If the target is a creature and the puppet is aflame, the creature must succeed on a DC 19 Dexterity saving throw or ignite in magical flames. The flames do 8 (1d12 + 2) fire damage each turn. A creature that takes this damage must make a DC 19 Constitution saving throw or have its hit point maximum reduced by an amount equal to the damage taken. The target dies if the fire reduces its hit point maximum to 0. The reduction lasts until removed by the greater restoration spell or other magic.

The flame can only be doused by dealing bludgeoning damage to the creature that is aflame from a magical attack.

Fire Spray (Recharge 6). The puppet exhales flames in a 15-foot cone. Each creature in that area must make a DC 19 Dexterity saving throw, taking 45 (10d8) fire damage on a failed save, or half as much damage on a successful one. Creatures that fail the saving throw catch fire; until someone takes an action to douse the fire, the creature takes 8 (1d12 + 2) fire damage at the start of each of its turns.

Swallow (Recharge 6). The puppet makes one bite attack against a Medium or smaller creature that is aflame. If the attack hits, the target takes the bite's damage, the target is swallowed, and the flame is doused. While swallowed, the creature is blinded and restrained, it has total cover against attacks and other effects outside the puppet, and it takes 20 (3d8 + 7) bludgeoning damage at the start of each of the puppet's turns, and an additional 8 (1d12 + 2) fire damage if the puppet is on fire.

If the puppet takes 40 damage or more on a single turn from a creature inside it, the puppet must succeed on a DC 19 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of the puppet.