A real intelligence would be able to either put together the information needed and fill in gaps with research or it would be able to tell you that it does not know.
"Hallucination" is yet another anthropomorphism of the model. A mind hallucinates; a model just produces incorrect results.
LLMs are very cool but I'm really sick of the "intelligence" branding. If a person who didn't know about something just confidently made shit up, I wouldn't call them intelligent.