Persona 6 Gimmick Theories

I made a post a long time ago about what possible theories would be for the new Persona 6 'gimmick.'

Persona 3 - Guns

Persona 4 - Glasses

Persona 5 - Masks

Metaphor - Veins? I haven't actually played Metaphor yet so I'm not 100%.

Anyway, now that we have the teaser with the neon green and grave stones and stuff, I was just wondering what new theories people might be cooking up.