Help me create a magic item

[Oramac]

I'm currently DMing a game in a homebrew world that might be called "medium magic". My players are all level 2, and instead of just saying "here's a cool thing" I want to let them choose what they get (to an extent).

So my idea for a magic item is to have them find a magical flask of weapon oil that was being experimented on by a crazy wizard. There's only enough oil to be applied to one weapon, and the wizards notes do not say what will happen when it is applied, only that something good will happen. So I'm looking for ideas of what that "something good" is.

I do not want to just make it a regular +1 bonus. Something more creative and fun is what I'm going for. Minor combat bonuses are ok, like changing a damage type, but beyond that I just want to give them cool non-combat benefits.

The party is:

Elf Rogue
Half Elf Wizard
Half Elf Paladin
Elf Monk
Human UA Ranger

My idea so far was for a bow:

"When applied to a bow or crossbow, the weapon becomes smoother and is warm to the touch. When the bowstring is pulled, a magical arrow/bolt is created and can be fired as normal. The arrow/bolt deals Force damage and is considered magical for purposes of overcoming resistance and immunity."

I'm also looking for ideas for swords, maces, daggers, staves, and monk weapons.

Wow. This got longer than I anticipated. Thanks for reading this far!

[Hudsonian]

Elf Rogue

Dagger: the hilt becomes slightly bulbous, there seems to me a stick string comming from the end. Using an action to say the command word shoots a spider-silk thread that sticks to the first object it hits. If the target is an unwilling creature, make a ranged attack roll opposed by a dexterity (acrobatics) check, on a success, the dagger is connected to the creature until cut or broken. The spider-silk can be released from the hilt slowly or stopped to suspend in mid-air. The silk can suspend up to 200 pounds and has 10hp.

Half Elf Wizard

The staff grows a hand at its tip. This hand can be controlled by the wizard holding the staff, and has the same grip strength as the wizard. Also the hand can be used to cast touch spells (essentially the Reach property for touch spells)

Half Elf Paladin

The sword has an eerie presence, twirling the sword quickly emits a keening sound that sets opponents off guard, by using an action to maintain the noise opponents have disadvantage on saving throws against fear.

Elf Monk

Rubbing it on his hands gives him the ability to "light" his hands, the monk can choose to have the light apear sourceless or it may be accompanied by illusary blue flame reathing his hands. The flames provide no warmth and cause no damage. (Light cantrip with ranges halved)

Human UA Ranger

Illusory arrow: Arrows shot from this bow appear to come from 5 feet to one side of the archer. Wisdom(perception) checks to discover the source are at disadvantage if no other action is taken.

[CursedRhubarb]

Upon application to a Dagger the dagger becomes a Burglar's Muse.

Once per day, refreshing at dawn, this dagger can be used after a failed attempt to pick a lock to make a second attempt with advantage using the blade. Success on this attempt severs the lock, preventing it from being re-locked and is audible from up to 10' away.

Would be a lifesaver for those times when picking the lock is the only safe way through, but makes it a lot harder to hide you were there and might draw attention if anyone or anything is too close.

[Oramac]

Thanks guys! I like all of those.

Any other ideas are more than welcome!

[Hudsonian]

If applied to a greatsword it creates a small area of Darkness that covers the entire blade. It has no other effects, however the creep factor of wielding darkness itself grants advantage on charisma (Intimidation) checks to subdue enemies of Good alignment. Attacks do count as magical for the purpose of overcoming resistances.

Edit: This is a permanent enchantment of the "Darkness" spell, and Devil's Sight would still see that it is merely a regular old Sword blade. The spell encompasses the same area that a sheath does.

Edit2
.................................................
You said crazy right? Applied to a sling, the oil transmutes all projectiles into tiny a random tiny creature. If the attack misses or does not do enough damage to kill the creature, it reviles you and slinks away to prepare it's revenge. Each creature must be different than the one before and a failure to declare what animal was produced reaps a DM disappointment penalty of -2 to the attack role.

Spear

The shaft changes to a light gray color with the word "Kumquat" inscribed around the base, saying the word causes the bearer to weigh double for 1 minute or until repeating the word

rapier

The damage type of the sword is changed to psychic damage. This is because the rapier has been transformed into a modern day fencing foil with buzzer included. The sheer discontinuity of the time line and random buzzing noise emanating from the handle causes mental distress equal to that of a rapier. This is not considered a magical weapon.

[CursedRhubarb]

For shenanigans and oddly useful for interrogation:
When applied to a Mace, the weapon gains a max of 4 charges, regaining 1d4 charges at dawn. Upon striking a creature with this weapon a charge can be spent to restore 2d6+Str mod hp to the target.

Zombies beware!
When applied to a bow:
An arrow fired from this weapon becomes consumed in holy fire and deals Radiant damage instead of piercing. The arrow radiates light in a 20' radius as it travels.

Why is the rum always gone?
When applied to a quarterstaff:
This weapon gains 5 charges that refresh every seven days at midnight. By expending charges the weilder can conjure 1 gallon of weak rum alcohol of a flavor they desire per charge used. This fluid is not strong enough to cause intoxication. (Yay, no more worries for water supply on travels)

[Aelyn]

Rapier of Precision: If applied to a rapier, the blade becomes exceptionally well balanced. Once per day, refreshing at dawn, the wielder can choose to double their proficiency bonus for a single attack. This does cause the attack to lose some of its force, so that attack does not gain the welder's STR or DEX modifier to damage.

Iridescent Bow: The wielder of this bow can, using a Bonus Action, cause the bow to become wreathed in an ever-swirling aura of light of all colours, shedding dim light to a radius of 30 ft. Arrows fired while the bow is activated take of some of this effect as they fly, causing then to deal elemental damage - instead of causing Piercing damage, roll 1d4 and consult the table below to see the damage type:

1 - Cold
2 - Lightning
3 - Fire
4 - Radiant

The wielder may use another bonus action to end the iridescent aura.

[Oramac]

Ahh these are great. I'm definitely writing them down and using them.

Thanks everyone!

[Zman]

The weapon becomes lucky, when it rolls a one to hit it is not an automatic miss, count it as an automatic hit instead. Bonus points for describing the success in ridiculous terms.

[Oramac]

The weapon becomes lucky, when it rolls a one to hit it is not an automatic miss, count it as an automatic hit instead. Bonus points for describing the success in ridiculous terms.

The guy playing the Monk is notorious for rolling 1s. I actually used something similar to this for his benefit, should the group decide to give him the oil. Good call!