"Looking to make a list of fun (or not so fun) quirks items might have. Can be for specific types of items (if so, say what it is) or any. "

d100 Random Item Quirks

1. Conduction - Metal Weapons - Weapon deals extra 1d6 lightning damage, but due to conduction you take half that damage. [/u/Craft57738]
2. Costly - Any Magic Item - You need to pay the item 10 sp after each combat, otherwise it loses its magical effects (the item absorbs the money). [/u/Craft57738]
3. Colorful - Any Armor or Weapon - The item changes color based on this cycle: Green, Blue, Yellow, and it repeats. (If it is armor it changes when you are hit, if it is a weapon it changes whenever you hit a creature with the weapon). [/u/Craft57738]
4. Loud - Any Weapon - Whenever you hit someone with the weapon, it screams out "BOOM!". [/u/Craft57738]
5. Smelly - Any - Gives off a smell that attracts vermin. [/u/Craft57738]
6. Scared - Any Armor or Weapon - Right before contact, the armor or weapon will scream loudly in fear. [/u/DeapSeaDarkness]
7. Rusty - Any Metal Object - Must be cleaned within 24 hours of the last time it was used, otherwise it becomes rusty and unusable. [/u/DeapSeaDarkness]
8. Moody - Any - Changes color based on the weilder's mood. Red - Angry, Blue - Jealous, Pink - Happy, Green - Scared, Purple - Guilty. [/u/wyverndarkblood]
9. Collapsable - Any Weapon - Can be folded down to 1/10th its original size. When drawn, it can expand either magically or mechanically. [/u/wyverndarkblood]
10. Cosmic - Any - Changes color during astronomical events (ex. solstices, full moons, and equinox). During those events, the item becomes blue with stars on it. [/u/wyverndarkblood]
11. Fashionable - Any - Will change its design to fit with the aesthetics of the owner (includes color and design motif). [/u/MutatedMutton]
12. Inexperienced - Any - Not using the item for a long time (7 days) makes it forget how to do its job. Next time it is used, the roll must be made with disadvantage. [/u/Craft57738]
13. Kinetically Powered - Any Magic Item - The item must be vigorously shook, cranked or pumped before use. It does not keep charge well so must be charged often (every 4 days), otherwise it cannot use it's magical effect. Said actions are also hard to do stealthily or with dignity. [/u/MutatedMutton]
14. Musically Inclined - Any - Upon hearing any melody, the item starts singing along or humming to it. [/u/Craft57738]
15. Poor - Any - After use, make a d20 roll. On a Nat 1, the item breaks. The item also naturally breaks after its third use. [/u/Craft57738]
16. Heated - Metal Weapons - The weapon is burning hot, causing it to deal an extra 1d6 fire damage. [/u/Craft57738]
17. Charged - Any Magic Item w/ Charges - The item holds 1 extra charge, and restores 1 extra charge whenever its charges are restored. [/u/Craft57738]
18. Divine Touched - Any - When the owner of this item is reduced to 1/4 or less of their total HP, the item will glow and restore 1d6 HP. The item will glow whenever the owner is within that threshold, however the healing is only once a day.
19. Bloodthirsty - Any Weapon - Once this weapon draws blood from a specific enemy, it will want more. Successful attacks on the original enemy deal an additional 1d4 damage. However, attacks made against other enemies are made with disadvantage due to the weapon targeting the original enemy. This effect ends either if the original target is killed or after 1 hour has passed.
20. Hefty - Any - This items weight is counted as double. [/u/Craft57738]
21. Featherweight - Any - This items weight is coutned as half. [/u/Craft57738]
22. Catchphrase - Any Attuned Weapon - Whenever you use your weapon to make an attack, it screams out one word of your choice. The word is determined based on whatever you choose during your next rest. (Limited to 2 words). [/u/Craft57738]
23. Giantslayer - Any Weapon - Weapon deals extra 1d6 damage to any enemy that is larger size than you. [/u/Craft57738]
24. Reckless - Any Weapon - Weapon has 2 on attack rolls, however your AC is decreased by -1. [/u/Craft57738]
25. Spooky - Any - The first time each day you engage in combat, a 10 ft radius sphere of darkness originates from you. Creatures with darkvision can see through it. [/u/Craft57738]