Spectre

Spectre is a pyramid-like piece of transparent plastic that you can place on top of a brightly lit smartphone screen in the dark and watch images seemingly float in mid-air.

What Spectre displays isn't a "hologram" in the physics sense because the smartphone screen isn't a coherent light source and the images aren't being produced by interfering light patterns. However, the product literature uses the word hologram so I guess we just have to go along with it and pretend.