This weapon is a magic dagger disguised as a sewing needle. When you hold it and use a bonus action to speak its command word, it transforms into a dagger or back into a needle.
You gain a +1 bonus to attack and damage rolls made with the dagger. While holding it, you can use an action to cast the mending cantrip from it.
Proficiency with a dagger allows you to add your proficiency bonus to the attack roll for any attack you make with it.