What's this icon on Instagram?

[SugarAndSpike]

What's the box between the "send message" and the heart please?

Ooh I've never seen that! Is it when you go to respond to a story?

It was on an old story.

I'd never seen it before either!

Thing is, I was stalking checking out an old acquaintance's account I clicked on the icon assuming it would give me an option of some kind but it just disappeared. Bit embarrassing if this person realises I've been lurking. Serves me right I suppose!

I think you see it when you're looking at highlights on their profile - it let's you scroll through the stories that are in that highlight and (afaik) doesn't notify them that you've looked.