1. Former Minister Fudge has actually eaten goblin pie. Of course, it was just the once, and he swore off it after that night because the meat was very tough and he found himself up for hours with a terrible case of Circe's Revenge.
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2. The crumple-horned snorkack does exist. Unfortunately for Luna, it's a cross between a thestral and an augurey, so only people completely without a sense of humor can see them.
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3. A wizard has walked on the moon. Most wizards don't even believe the Muggles have done it. But "Ballsy" Beauregard Buchanan or West Yorkshire managed the feat on October 12, 1972, by combining Apparition with a modified, full-body bubble-head charm. It was a spectacular achievement that sadly went almost completely unknown, since he was crushed by a stampeding umgubular slashkilter moments after his return to Earth. Luna happened to be nearby and was lucky enough to hear his shouts of delight at his success before she wandered away. Buchanan's last words were "I am a fabulous geni-ugh!"
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4. There were nargles in the mistletoe at Hogwarts during Umbridge's reign. No one believed Luna's first pronouncement, and she never repeated it since one of the nargles asked her very politely to keep quiet about it.
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5. Luna's mother is there, elbow-to-elbow with Stubby Boardman, just behind the veil in the Department of Mysteries. Hundreds of people are there, watching and waiting for their loved ones to come through. Harry believed this, too, for a little while, but then Dumbledore's death took away all Harry's faith in magic.