D&D 5E Make a Flawed Magic Item

[Caliban]

Boots of Excessive Springing: These boots triple your jump distance, however when you jump you always jump your maximum possible distance (i.e. 3 x your str score on a running jump).

If you do not have enough movement left to complete the jump, you end your turn in mid-leap and land on your next turn.

If your jump carries you into a wall or ceiling...you bounce or ricochet off and continue the jump in a new direction until it has completed.

Whenever you roll a 1 on an ability check, saving throw, or attack roll you will inadvertently trigger a jump the next time you move.

 

[Krachek]

Frenzy armor.
You are constantly under the effect of the barbarian’s reckless attack feature.

 

[Nevvur]

A lot of these seem more like straight-up cursed magical items, not flawed as requested by the OP.

 

[Rossbert]

Most of them have SOME benefit, but the real trick is having the drawback be a problem but not so much that you'd never use the darn thing. No I do not have any idea what is good enough.

Javelin of Static Discharge - Functions as a normal Javelin of Lightning, except the wielder must also make the Dex save. They take half damage on a failure and no damage on a success.

Orb of Amplfication - This orb grants a +2 bonus to magic attack rolls and DCs, but every spell cast uses the highest level slot available as long as it is attuned. This item cannot be attuned by warlocks.

 

[TiwazTyrsfist]

Flame-Burster - This Longsword, when drawn and used bursts aflame. On a normal hit, it deals +1d4 fire damage. However, it has an expanded critical range (19-20), and on a Critical Hit it emits an ENORMOUS BURST of Flame. This deals an extra 2d10 fire damage to the target. This also deals half as much fire damage to the wielder.


Soul-Frost - This Shortsword is enchanted with overcharged Ice Magic. On a successful hit, it deals +1d8 Cold Damage. On a Crit it deals an additional +1d8 (2d8 total) Cold damage. However, the cold constantly seeps into the owner. As long as the sword is in your possession and attuned to you, you are always cold. In normal weather, you suffer as if under extreme cold, making a dc 10 con save every hour unless you are properly attired for cold weather or magically protected. In actual extreme cold you must make the save every half hour with disadvantage. You are also vulnerable to Cold Damage.

 

[Dannyalcatraz]

From an old campaign...

Healing Club of St. Cuthbert: HEALS target creature. To operate, hit creature with the club, doing normal (nonmagical) club damage. (IOW, it heals the creature of all damage except the club strike.)

 

[Adamant]

Defender's Shield (Legendary, requires Attunement)

This large +3 shield causes all projectiles and attacks to target the wielder and grants a +3 to saving throws against area of effect damage, but confers a -5 penalty to attack rolls.


Martyred Defender's Shield (Rare/Very Rare, whatever is actually balanced)

This large shield causes all projectiles and attacks to target the wielder, but confers only +1 armor class and adds a -1 to saving throws against area of effect damage.


My eldritch knight would love either of these, since he has an armor class of 27 if he uses Shield, but can't get enemies to attack him in the first place.

I know that there have been two concepts about this before, but I figured i'd add my version. Also, the legendary shield is pretty different from the others.


Ring of Shadows (Rare/Very Rare, requires Attunement)

Functions as Ring of Invisibility, but when used the wearer must make a DC 15 wisdom save (DC 12 for the Very Rare version) or take 2d10 psychic damage and be unable to use the ring again for 1d4 weeks (3d6 days for the Very Rare version).

This ring takes inspiration from the One Ring and the way the world looked when you were invisible. For characters with a good wisdom save, this ring is a more common version of the Ring of Invisibility.

 

[Dannyalcatraz]

Spider shoes: these shoes enable the wearer to walk on walls and ceilings as if they were a spider. However, with each step, they produce an audible *th-POK* sound, regardless of surface.

Thinking cap: this intricately made metal hat is covered with moving parts resembling the inner workings of a clock. When worn, it doubles the wearer’s bonuses to Intelligence-based skill checks. After it has aided the wearer to succeed in 1d4 successful checks, the wearer suffers intense hunger pangs and debilitating migraines (-2 to all rolls) which persist until the cap is removed for at least one hour and the wearer has a decent meal.

 

[Eltab]

Auto-scrying mirror - (Requires attunement) Looking into this mirror automatically allows the user to remotely view the attuned creature as if it were the subject of the Scrying spell.

If I understand this correctly, it is useful to Person B if:
- Person B is able to cast Scrying
- Person B gives the "magic mirror" to Person A
- Person A attunes himself to it
- Person B arranges to steal the mirror from Person A
- Person A never finds out about it, and never tries to get his stolen magic item back
- AND Person A is somebody whom it is worthwhile to spy on in the first place.

Am I following you correctly?

 

[Eltab]

My favorite magic toy is a Basket of Everlasting Provisions

Slightly cursed versions:
- Dedicated to a deity, it will only provide food to a person of that faith. All you heretics and infidels can starve, for all it cares.
- The Basket thinks you need to go on a diet.
(1) You get unpalatable unappetizing foods. Celery, oatmeal, lettuce, ...
(2) You get a fad diet. A half-month later you get a different fad diet.
(3) You get food the Basket believes appropriate to your assigned class, in the society where it was created. Bread and water is peasant food, &c.
- The Basket only serves fully-organic food. It hasn't been washed or treated for bugs / germs or anything. (xx% chance of food poisoning)
- The Basket spent a lot of time in the presence of an oytugh, and now provides what IT considers appetizing foods.
- The Basket was a gift to a mind flayer. Guess what you get served?
- The Basket was crafted for a famous cutting-edge chef in an exotic land. The foods it serves are fully nutritious, but doesn't look like anything that "normal people" eat.
- The Basket was cursed by a Druid. When it serves you meat, your group has a "random" encounter with a very hostile example of that animal within 24 hours.
- The power of the Basket is dependent on the bounty of the surrounding land. You will be fine unless there is famine in the land, you travel into a desert, lost at sea (no "land") ...