Fountain Harp

Wondrous item, very rare (requires attunement)

You must be proficient with harps to attune to this instrument. This traveller's harp doesn't have strings: instead, thin streams of water pour from the top. The streams vanish into nothingness before reaching the bottom of the harp. When played, the harp emits a tone like a raindrop hitting metal. Even if the harp is held on its side, the streams of water fall toward the bottom of the harp. The harp weighs 3 pounds and requires two hands to play.

Songs of Water. While holding the harp, you can spend 1 minute playing a special song from it. At the end of the minute, you cast one of the following spells from it (save DC 16): control water, create or destroy water (3rd-level version), or water walk. If a spell requires you to concentrate on it, you must use an action on each of your turns for the duration to continue playing the harp.

Summon Water Elemental. While holding the harp, you can use an action to play it and cast the conjure elemental spell from it. This version of the spell can only call forth a water elemental, and it doesn't require your concentration. However, you must use your action to continue playing the harp on each of your turns for the duration of the spell. The spell ends early if you cease to play the harp, at which point the elemental immediately disappears. Once this property of the harp has been used, it can't be used again until the next dawn.

Watery Discord. If you're not in water, you can use action to pluck a string from the harp to cast the acid arrow spell from it, using a spell attack bonus of +8; the spell deals no damage if you miss with the attack. If you're underwater, you can use an action to cast the thunderwave spell from it (2nd-level version, save DC 16); a creature that succeeds on the saving throw takes no damage from the spell.

Her strings, like whispers spun from rain,
Could stir the sea or soothe its pain.