Magic Items Inspired by JoJo's Bizarre Adventure: Stone Ocean
Since I haven't read the manga, I don't have enough knowledge to form a meaningful opinion on Stone Ocean yet, but what I've seen of it so far has me tentatively placing it as my third-favorite part of JoJo's Bizarre Adventure. More relevantly, the fact that only 12 episodes have been released to date means that I wasn't able to come up with 20 items. Rather than pushing myself to stretch for ideas to hit that number, I decided to make up the difference with some extras from previous parts. Looking back over those was an interesting experience, because it's easy to get caught up in the present part and overlook what came before (specifically, I'd expected at least one item from my Golden Wind extras to make the list, yet actually looking at those in comparison to what I had from previous parts left me unimpressed).
Without any further ado, here are 14 magic items inspired by Stone Ocean, plus a selection of my favorite leftovers from previous parts to round out the list:
1: String of Ears
This 50'-long string can be embedded in the user's body through an index fingertip. When extended, it lets the user hear sounds at its far end in addition to their current surroundings.
2: Intimidating Thread
This 2'-long red thread can be commanded to attack a target visible to its owner. It turns invisible and ties itself around the target's neck tightly enough to impede breathing (without posing an actual threat of asphyxiation) until commanded to relent by its owner. Any injury to the target while the thread is around their neck causes the thread to fall apart.
3: Diminution Doll
This fibrous husk doll can be placed on a target to shrink it and its carried possessions (including the doll itself) to 5% of their normal size over 1 round. The owner can end the effect by commanding the doll to return to its dormant form. If the doll and target are separated before the effect is ended by the user, the effect ends instantly, and the doll animates to kill the target (level/HD as its owner; movement, damage, and AC as a wood golem; vulnerable to fire).
4: Personal Observer
This mouse-sized paper figurine can be commanded to track the location of a single creature that its owner can see. The figurine can ride air/gas currents and pass through water to get within 10' of the target, from where it provides a mental image of the target's location to its owner. The figurine hides itself as well as a mouse and reappears at its owner's side if destroyed.
5: Bone of Mental Sanctity
This pitted piece of pelvic bone digs into the owner's flesh whenever they are under a mind-altering magical effect, dealing 1 hit point of damage and allowing them to roll a save to negate the effect (including effects that do not normally allow for a save). It repeats this once per round until the effect is ended. If the owner is under multiple mind-altering effects, the damage allows for making a save against each of them.
6: Twinning Talisman
When this thumbnail-sized paper talisman is applied to an object (up to the 100 lbs), it duplicates the object and adheres to the duplicate. When it is removed, the duplicate snaps back to merge with the original (the original object and any creatures caught between the pair take damage as a fall equal to the distance between the two objects, save halves). The duplicate fades away if it is ever more than 60' from the original, leaving the talisman to fall at its last location.
7: Cuffs of Bondage
These two locking wrist cuffs explode if they are further than 150' apart or if the locks are tampered with unsuccessfully, damaging the wearers and anything within 5' of them as a 10th-level fireball (save halves).
8: Skinwalker's Headdress
This iron headdress allows its wearer to transfer their consciousness into a corpse by touch. The host body retains any existing damage, continues to decay, and is susceptible to desiccation. If it goes more than 100' from the wearer's original body, the original body dies and the transfer is permanent (note that the host still decays as it is not alive but merely animate).
9: Test of Avarice
This simple gold trinket attracts the attention of thieves and sends a mental signal to the owner whenever it is stolen.
10: Gambler's Pact
This three-pronged metallic claw enforces bets that its owner is a part of. Once any party involved in the bet recognizes it has either lost or cheated, if they do not pay what they owe immediately, the claw summons a spirit to collect the wager by force (or something belonging to the debtor that can be sold for equivalent value, if the debtor cannot pay the wager directly). Interacting with the spirit by mundane means is impossible; for magical interactions, treat it as a formless invisible summoned devil.
11: Potion of Contagious Weightlessness
This vaporous yellow potion makes the imbiber and anything they touch ignore gravity for 1 hour.
12: Isolation Cloud
This humanoid cloud can be worn as a full-body suit, providing protection against temperature extremes and low air pressure (including vacuum) for up to 5 minutes per use. Each instance of physical damage taken while the suit is in use reduces its duration by 30 seconds. The use duration is restored when the cloud spends 5 minutes in a normal environment.
13: Sphere of Escaping
This fist-sized glass sphere contains two liquids separated by thin glass membranes. If the liquid are mixed, they explode. The resulting pressure wave and glass shards deal damage as a 2nd-level fireball in a 10' radius (save halves), and the reaction creates a 15'-radius cloud of thick caustic vapors, obscuring vision and causing severe irritation if contacted or inhaled. The vapors dissipate after 1 minute or if exposed to moderate wind.
14: Carrier's Manacles
This set of miniature manacles can be attached to a pigeon or similar bird, causing it to obey commands to pick up and return an object up to 5 lbs. The commands can include locations for pick up and return, the time, and the size/shape of the object. The object will not affect its flight.
15: Sack of Selective Safeguarding
This sack can preserve severed body parts, up to the size of an average human's torso. It will not affect complete bodies, regardless of whether they are stored whole or in pieces.
16: Tiara of Continuing Life
This unihorned tiara gives its wearer a flaming skull countenance. If it is worn for at least 1 day, the wearer can eject their brain on death and attempt to possess a new body (the disembodied brain has the wearer's level/HD, movement and AC as an intellect devourer, stealth as a rat). Dead bodies are possessed and overtaken automatically. Live bodies require grappling for 1 round (5 rounds if done stealthily), after which the brain infiltrates the body and may overtake it as a sentient magic item; after 1 week, the takeover becomes permanent. Undead bodies are unaffected by possession attempts.
17: Imperative Vitae
This hollow, head-sized glass sphere contains thick, translucent, milky-white ooze. The ooze is highly acidic. If the ooze is consumed, it sends the consumer into a hungry frenzy that lasts until they have eaten organic matter equal to their body weight. They take halved damage during the frenzy and are immune to mind-altering effects. A fresh sphere holds six doses of ooze.
18: Lyre of Candor
This lyre plays the user's true intentions, speaking the thought at the forefront of their mind when plucked.
19: Mute Mask
This faceless mask allows its wearer to cry eyeballs. Putting them in someone's mouth renders the person mute. The muteness lasts 8 hours if the eyeball is swallowed.
20: Helping Hand
This severed hand can be commanded to perform basic domestic tasks. It smells of decomposition and decays over the course of 1d6 weeks.