As an aside, in BrE we use "Scooby-Doo" as rhyming slang for the word "clue".
- What's that?
- I haven't got a Scooby Doo (means "I haven't got a clue", which means "I have no idea at all")
Sometimes it's shortened to just "Scooby" ("I haven't got a Scooby").
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