Eye of Ghaunadaur

Wondrous item, legendary (requires attunement by a druid)

This amulet, crafted to resemble a small spider, has eight badly tarnished golden legs. It hangs on a gold chain in a similar state of disrepair. Despite its apparent age, the amulet's golden components resist all attempts to deform or detach, as well as any attempts at polish or restoration.

The spider's thorax is made of a single dark emerald, whose depths appear completely black when viewed head on. The abdomen of the artifact is an ornately-decorated eye, which appears to be made of glass yet instills a sense of foreboding when you stare into it. Out of the corner of your vision, you could swear the eye darts about and even blinks, but it remains still when you look at it.

While attuned to the Eye of Ghaunadaur, your Wild Shape ability is altered in the following ways:

When you use Wild Shape, you must choose a Monstrosity to transform into, not a Beast.

While not wearing the Eye, you cannot use Wild Shape.

If your chosen form has any innate spellcasting, you gain it, using your Wisdom as the spellcasting ability.

While transformed, the Eye of Ghaunadaur hangs from your neck, either from a golden chain or a leather collar.

If the Eye is removed from you while transformed, you cannot change back to your original form. Dropping to 0 hit points without wearing the Eye renders you unconscious. Placing the Eye around your neck again will cause you to revert immediately if any of the normal conditions for reverting from Wild Shape are met.

If you remain transformed into a Monstrosity for more than 24 hours, you begin to lose any memories related to your original form. After 72 hours all recollection of your former self is lost. Your memory can be restored with a Wish spell, but will begin fading again after 24 hours if you do not reobtain the Eye.