Book Golem

False Appearance. While the Book Golem is still, it is indistinguishable from a scattered pile of books.

Ever-shifting Form. The Book Golem's make-up is never constant when moving or upright. As such it cannot be grappled, restrained, or become invisible. 

Arcane Creation. As regular books enchant the Book Golem, they cannot be charmed, frightened, blinded, deafened, petrified, or poisoned. It is also immune to any effect which would alter its form.

Multiattack. The Book Golem makes two fling attacks and one squash attack, or two squash attacks.

Squash. Melee Weapon Attack: +7 to hit, reach 10 ft., 1 target. Hit: 4d8+4 bludgeoning damage. 

Fling. RangedWeapon Attack: +7 to hit, range 30 ft., 1 target. Hit: 2d4+2 bludgeoning damage. The Book Golem flings one of its books at a target within range.

Book Swap. As a bonus action once every turn, the golem can extend some of its damaged books, draw from the piles of books nearby, and regain 2d10 + 3 health back. When the golem does this, the PC's on the side where the books swap happens, may take opportunity attacks against the books. They will have to beat the regular armor class but an attack roll of a natural 18-20 will count as a crit.

Disperse and Reform. Whenever the Book Golem is subject to a Dexterity saving throw, it can shoot its books outwards. It takes no damage from the effect (unless it engulfs a 10 ft. radius around the Book Golem) and all creatures within 10 ft. of the Book Golem must make a Dexterity saving throw or take 2d8 bludgeoning damage as books bludgeon them and then reform into the golem.

Book Golem's can take 4 legendary actions per encounter. 

Storm of Paper. 1 Legendary Action. With a burst of arcane energy, all of the books on the Golem open up and send their pages flying toward enemies. It can target every creature in a 15ft. wide by 75ft. long tube. Every creature caught in the tube must make a Dex Saving Throw, dc16. On a fail, the creature takes 5d4 slashing damage and is knocked prone. On a save, the creature takes half damage and remains standing.

Leather Bind. 3 Legendary Actions. The Golem grabs a book from off the ground and rips the pages out, leaving the leather. It will then make a Strength check to grapple a creature and bind them in the leather. It will require an STR saving throw dc19 from the enemy. On a fail, the creature is grappled and restrained by the leather, leaving the golem to make other attacks as normal. The creature grappled by the leather must make an STR saving throw at the start of its turns. These saves will have a dc16 STR in order to break free from the leather.

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