I can see a man eating dinner with his wife when suddenly the diner is exchanged with a giant octopus party and the man, so small beside the massive 8 legged boisterously drinking ... Octopus...looks to his right and sees a giant squid lunging for its face.(I was trying to think of another word above, it just came to me. Squid/octopus?
See in my world / if someone is hallucinating they need help to be called out if the door. Maybe some people are happier in other dimensions, where leprechauns run freely perhaps:).. But instead of telling people they don't exist I think / ok they do exist -- just back away, and close the door. Or even just turn away.
Not denied the reality.