Description: There are many types of monster rings and each one is slightly different in style and appearance. However, they all have a gemstone embedded in what looks like a golden eye. They are also naturally large but will shrink down to fit a finger if anyone is foolish enough to put on the ring. 

Monster Curse: Anyone who places the ring on their finger will not be able to remove it. Initially, nothing will happen to the victim apart from not being able to remove the ring. However, if a person wears a ring and takes a long rest, they will awaken from the rest and find themselves transformed into a monster. All of the victim’s Strength, Dexterity, Constitution, and Charisma ability scores will change to the basic stats of the creature as listed in the Monster Manual. Wisdom and Intelligence scores are unaffected. The victim will lose the ability to speak any language but may communicate with others telepathically if a spell or item gives them the ability. Players may retain their levels, classes and still use class skills when reasonable. Spellcasters will no longer be able to cast spells with somatic components but may cast non-somatic spells. Martial classes will no longer be able to wear any armor. Depending on the creature, the victim will lose the ability to wield weapons as well.

Here are the various known monster rings and their corresponding gemstones:

Uncommon Monster Rings

Rare Monster Rings

Other monster rings might exist.

Curing the monster ring curse – Cutting the ring off does not restore the victim to their normal body. Most of these rings are imbued with a trigger action that can cure the victim. The trigger action could be something direct such as climbing a really tall mountain or serving a particular deity for a year or the trigger could be something more abstract like learning the value of friendship or finding true love. It all depends on who created the ring and why. If a trigger action is present, the victim will know of it through a dream they received during the long rest when they were transformed. This will become a recurring dream. The dream may be clear in its meaning or vague depending on the nature of the ring. A victim of a monster ring can also be cured with a Greater Restoration or a Wish spell or if the ring is destroyed and the victim survives its destruction. 

Destroying a monster ring – A monster ring can be destroyed by dragon fire or a destructive spell at least level 6 or higher like Disintegrate or Delayed Blast Fireball. Preferably, this happens when the ring is not attached to a victim.