Mount Spellbook

Allows you to ride mobs/players. Allows control of certain ridden mobs when held.

Type: Gods

Lore:

Allows the holder to
ride any mob or player.

If you are attacked by the player you are riding, you will be forcefully dismounted.
If the entity that you are riding teleports more than 5 blocks, you will be forcefully dismounted.

Controllable Mobs

When holding the ride book in your hand, you are able to control certain mobs.
Elder Guardian, Wither Skeleton, Stray, Husk, Zombie Villager, Evoker, Vex, Vindicator, Illusioner, Creeper, Skeleton, Spider, Giant, Zombie, Slime, Ghast, Zombified Piglin, Enderman, Cave Spider, Silverfish, Blaze, Magma Cube, Wither, Bat, Witch, Endermite, Guardian, Sheep, Cow, Chicken, Wolf, Mooshroom, Snow Golem, Ocelot, Armadillo, Bogged, Breeze, Iron Golem, Rabbit, Polar Bear, Parrot, Villager, Turtle, Phantom, Cod, Salmon, Pufferfish, Tropical Fish, Drowned, Dolphin, Cat, Panda, Pillager, Ravager, Wandering Trader, Fox, Bee, Hoglin, Piglin, Zoglin, Piglin Brute, Axolotl, Goat, Allay, Frog, Tadpole, Warden

There is a known and very weird bug that mounting a mob that has just spawned will not allow you to control it,
you may need to "wake up" its AI by punching it or waiting for it to target you if it is hostile.