Chaos Reins

Wondrous item, uncommon (requires attunement)

This amulet is made from a repurposed horse's rein. While wearing it, you are considered proficient in the Animal Handling skill whenever you make a Wisdom (Animal Handling) check to interact with a Large or larger beast.

While wearing the amulet, you can use an action to cast the find steed spell from it. When you do, roll a d8 to determine what creature is summoned by the spell, using the table below. If that creature has already been summoned since the last dawn, the spell fails, the action is wasted, and this property of the amulet can't be used again until the next dawn. Otherwise, the steed appears beneath you (using the creature's normal statistics), allowing you to mount it as part of casting the spell. This version of the spell has a duration of 1 hour, and when it ends, the steed immediately disappears. The spell ends early if you dismiss the steed, if it's reduced to 0 hit points, or if you dismount it.

Curse. This amulet is cursed, and becoming attuned to it extends the curse to you unless you're a creature of chaotic alignment. Whenever the find steed spell fails to cast as a result of attempting to summon a creature that had already been summoned since the last dawn, that creature appears in an unoccupied space within 10 feet of you. The creature is hostile toward you and takes its turns on initiative count 20. The creature remains for 1 minute or until it's reduced to 0 hit points.

The haughty knight gave a confident laugh and yelled "To me, my magnificent steed!"
Nothing happened, and the color drained from the warrior's face.
"Uh-oh."