Brighella's Guitar

This guitar is brilliantly painted with triangles of bright color. While attuned, you gain an _expertise die_ on Performance checks made with this guitar. Additionally, once per day, you may use an action to cast __bestow curse_ as a 5th-level spell, without spending a spell slot. However, the curse is always _disadvantage_ on Dexterity _ability checks_ and _saving throws_ and each failure is followed by a slapstick sound effect.