Very Rare Wondrous Item 

A jade figurine of an elephant-like creature. You can use your action to speak the command word and to throw the figurine to a point on the ground within 60 feet of you. The figurine transforms then transforms into a huge and deadly jade construct called the Jade Bulwark. The construct will turn again into a figurine after 1 minute or until it goes to 0 Hit Points. 

Once the Jade Bulwark turns into a figurine again, it cannot be transformed again for 7 days.

Jade Bulwark

Huge Construct, Unaligned
Armor Class: 27 (Natural Armour)
Hit Points: 312 HP (25d12+150)
Speed: 40 feet
STR: 25/+7
DEX: 6 /-2
CON: 23/+6
INT: 3/-4
WIS: 3/-4
CHA:5/-3
Damage Immunities: Poison, Psychic; Bludgeoning, Piercing and Slashing from nonmagical attacks
Condition Immunities: Charmed, Deafened, Exhaustion, Frightened, Paralyzed, Petrified, Poisoned
Senses: Passive Perception 6
Languages: Understands the Languages of its Creator, but doesn’t speak
Challenge: 13
Proficiency Bonus: +5

Cursed Figurine.

• The Jade Bulwark is usually found in the form of a small jade unmoving figurine, and if an action is used to throw it on the ground and speak a command word, it transforms into a huge deadly construct.
  However unlike other figurines of its kind, the bulwark is instantly hostile to all creatures in sight and does not obey any commands.
  • It remains in its huge form for one minute, becoming a figurine once the time runs out, or once it goes to 0 Hit Points

Jade Armour.

• The Bulwark’s armour is nigh impenetrable, but it cracks under extreme conditions. The Bulwark’s AC is reduced by 1 (to a minimum of 16) each time it takes at least 15 Fire or Cold damage, and each time it deals damage to itself.

Furious Charger.

• If the Bulwark moves at least 20 feet in a straight line before making an attack, it deals additional 1d12 bludgeoning damage
• Each time it misses an attack, the Bulwark moves 10 feet forward. If it hits a sturdy solid object. The bulwark takes 5d10 damage and must make a DC 11 Constitution Saving throw, being stunned until the end of its next turn on a failure. The hit object takes an equal amount of damage and can be destroyed by the collision.
  • The Bulwark can make a Gore attack against any creatures in the area of the movement that takes place after a missed attack. Missing this attack does not trigger additional movement. If this attack hits a creature of size large or bigger, the Bulwark won’t move any further with its charge.