Instax is the modern equivalent of Polaroid - cameras that spit out real instant photos there on the spot. Not great image quality, and somewhat pricey per shot, but good fun. And yes, it’s proper instant film with chemistry, so you can watch the image develop right there in your hands.

Caveats/gotchas: IIRC the Instax line also includes hybrid cameras which are basically just digital cameras with built-in printers. Still neat, but less cool than the standard line in my opinion. Also, Polaroid do still exist in zombie corp fashion, but they mostly just make digital cameras/printers and the film for their old cameras is crazy expensive. Unless you’re deeply committed to using an old Polaroid camera, it’s not worth it compared to Instax.