This instrument seems to be some kind of invention by a maniacal artificer. On the side of the instrument the words: ACD/P Feedback Flood. Active Charge Displacer / Prototype. Etched into the metal. There is a scrap of parchment stuck to the back, it seems to be notes from the inventor, some of the words are blurred or torn. They say:

Pu.... haz. al. .. my .rain

Anyw.. he… Wond.rwa.l

Yo.ve b..n Thu..ers..u.k!

This instrument has 9 charges and recharges 1d6 + 3 charges when you finish a long rest. While attuned to and holding this instrument you gain a + 2 to spell attack rolls.

Ride the lighting

• When you cast a spell that deals lightning damage that originated from within 5ft of you, you can expend 1 charge to follow the spell for up to 100 ft.

Through the Fire and the Flames

• While attuned to this instrument you have resistance to fire damage.

The abilities below are secret until the phrase is decrypted and you say it out loud

Purple Haze

• You can use an action to speak the Command Phrase and expend 4 charges to cast confusion.

Wonderwall

• You can use an action to speak the Command Phrase and expend 5 charges to cast wall of force.

Thunderstruck

• You can use an action to speak the Command Phrase and expend 3 charges to cast lightning bolt.

Notes: a bard