Is there an item in DND 5e that will cast Alter Self?

The 5th level party I DM for just found a Hat of Disguise. Our Rogue (Thief Archetype) is fascinated by the endless possibilities, but slightly put off by the shortcomings of the Disguise Self spell it casts. She has had a conversation with our spellcasters, and her player has asked me whether they could find an item that would cast the more powerful Alter Self spell. I see much potential for entertaining mayhem in this.

Is there an item that casts Alter Self, say, once a day? Even homebrew? (If I can’t find anything official, I’ll homebrew it anyway.)

I have skimmed through the DMG and only found the Wand of Polymorph, which isn’t quite what we had in mind. The Infiltrator’s Key is way overpowered for this.