I’ve been using holograms in my halloween decorations for years now. I also have a robot (Buoyant Bob… he’s a giant chubby-pill-shaped beach ball that hands out the candy…) that gets dressed up. My favorite year was the Phantom of the Opera theme, where we had holographic organs (including several that were animated up in the air for him to go play with.). The holographic organs on the ground, would make “music” if the kids “played” them. (okay, so it was like 5 chords, and the resolution was kind of laughable.)

it was my favorite because we had kids getting dragged away by parents trying to suggest that if they wanted to fill their bags, they’d have to stop playing with the organs. (pretty sure those parents are stealing their hard-earned candy. jerks.)

to put it simply, there’s no such thing as a photorealistic or convincing hologram. mine use fog screens and multiple projection sources with very careful angles to record it. even if you can do full color- and you can’t- it would be super obvious the moment a projector got nudged or it’s framerate got out of sync.