Bulette (Dire)

Armor Class 19 (natural armor)
Hit Points 347 (20d12 + 120)
Speed 60 ft., burrow 50ft.

Skills Perception +6
Senses darkvision 60 ft., tremorsense 60 ft., passive Perception 16
Damage Resistances bludgeoning 
Languages --
Challenge 15 (13,000 XP)

Standing Leap. The bulette's long jump is up to 40 feet and its high jump is up to 20 feet, with or without a running start.
Siege Monster. The bulette's deals double damage to buildings and structures.
Blood Frenzy. The creature has advantage on melee attack rolls against any creature that doesn't have all its hit points.

Actions

Bite. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 56 (8d12 + 4) piercing damage.
Slam. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 20 (3d8 + 7) bludgeoning damage.
Deadly Leap. If the bulette jumps at least 15 feet as part of its movement, it can then use this action to land on its feet in a space that contains one or more other creatures. Each of those creatures must succeed on a DC 16 Strength or Dexterity saving throw (target's choice) or be knocked prone and take 27 (6d6 + 6) bludgeoning damage plus 27 (6d6 + 6) slashing damage. On a successful save, the creature takes only half the damage, isn't knocked prone, and is pushed 5 feet out of the bulette's space into an unoccupied space of the creature's choice. If no unoccupied space is within range, the creature instead falls prone in the bulette's space.