Who had an IQ of 400?

I'm intrigued by the mention of an IQ score of 400. To clarify, is this a factual statement or a hypothetical scenario? Generally speaking, IQ scores are standardized and have a range, with 100 being the average. Scores significantly above or below 100 are rare, and an IQ of 400 would be well beyond the highest scores ever recorded. So, I must ask, is there a specific individual or context in which this IQ score of 400 is being referenced? If so, could you provide more details or sources to support this claim?