Ball of Blades

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

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

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

Trampling Ball. When the ball moves, any creature whose square it moves though must succeed a DC 20 Strength saving throw or be pushed 5 feet away and knocked prone.

Roll Out. When the ball moves through a creature's range and provokes an opportunity attack, the creature has disadvantage on the attack. The ball can also use the Dash or Disengage actions as a bonus action.

Multiattack. The ball makes four blade attacks.

Blade. Melee Weapon Attack: +10 to hit, reach 15 ft., one target. Hit: 11 (1d12 + 5) slashing damage.

Slam. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 15 (3d6 + 5) bludgeoning damage.

Blade Storm (Recharge 5-6). The ball unfurls its blades and spins around rapidly in place. Each creature within 15 feet of it must succeed a DC 20 Dexterity saving throw. On a failed save, it takes 31 (4d12 + 5) slashing damage and is bleeding for one minute, unless it is a construct or undead. While bleeding, the target takes 9 (2d8) damage, until either the effect ends or the creature is healed. On a success, it takes half damage and is not bleeding.