Player buys a magical cape that’s become a joke

Not sure what flair this should go under so I simply did other. Apologize if this isn’t the right one.

One of my players (Druid 5.5E) went into an oddities and trinkets store and bought a dusty cape he found for 30 gold that he recognized as magical. I called it the cape of billowing wonder. When he puts it on and stands still the cape simply … billows in non existent wind.

It’s become a hilarious laughing joke at the table as we sparingly mention the cape flapping lightly inside and how people are looking at it strangely and side eyeing it.

Thing is, I want this thing to eventually become something. I was kind of thinking something may unlock sentience or perhaps it becomes a tool eventually to get the group out of serious trouble etc but figured what better place to brain storm some awesome ideas than with fellow DMs.

Pertinent information …

Group of 5 PCs Druid, rogue , barbarian, warlock, cleric
In Rime of the Frost maiden
5.5E