David Gray spotted and posted on Twitter a featured snippet that expands and has multiple drop down expansion menus. If you search for [garage conversion] on mobile, you probably will see it for yourself. It shows the featured snippet, with the images and text and then below it, it has categories that you can expand that show a section for cost, plans, building regulations and insulation.

Each section comes from a different site, for the most part. Here is a GIF of it in action:

Here is a static image of it all closed:

It seems like to be an extension from the multifaceted Google featured snippets.

Forum discussion at Twitter.