Wondrous item, uncommon
You can use an action to blow this whistle. When you do, you and up to four willing creatures of your choice within 30 feet of you that can hear the whistle are affected by your choice of either the water breathing or water walk spell. If you're underwater, the range of the whistle increases to 60 feet, and it sounds like a merfolk's song. Once this property of the whistle has been used, it can't be used again until the next dawn.
If you give the sea a song, it's sure to dance with you.