With sort of, but not very sincere apologies to a well-known horror writer whose name may or may not rhyme with Even Thing, but who certainly isn’t the ONLY writer to fall back on this trope…
“Okay, Dad, you said you’d explain it when I was older, and now I am. And in fact, last night it happened AGAIN. They’re dead, aren’t they?”
“Who?”
“Dad, come off it. You know exactly who. That nice couple that showed up last night. You let them stay in the old Hockstetter place, and get eaten by the carnivorous frogs.”
“It’s the Rain, son. You probably don’t remember the last one, but…”
“Don’t remember it? Are you kidding? I was seven years old. It was the most terrifying thing that had ever happened to me! The clouds came, the carnivorous frogs fell everywhere, we spent the night sealed up in the basement, and then in the morning that couple had been eaten. And the frogs all evaporated. the next morning. Why didn’t we warn them if it happens every ten years?”
(Sigh) “We did warn them. We always warn them.” <Deep, Pensive Breath> “It’s time to tell you the Awful Secret About Our Village, Son.”
“I think I just said it. We let this happen to people every ten years? Why?”
“Well, if we didn’t, the frogs might not evaporate. They might stick around and eat all of us.”
“Seriously? What makes you think that would happen? Has it ever happened before?”
“Well, of course not! Because we always let the frogs eat the visitors.”
“Really? How did we survive the first rain of frogs?”
“Eh? I told you: we let the visitors get eaten.”
“So, what, someone showed up and said, hey, here’s how this will work? Innocent visitors will arrive, you have to warn them off, but they won’t go, so let them stay in a rickety house and let them die, or carnivorous frogs will rain from the sky and kill you all? And did all the people in the town hurt themselves laughing?”
“Well, I never heard about anything like that. My grandfather, he just told me…”
“Really? Okay, let’s think about this: One day a young couple came to town, and wanted to stay. And somehow, that night, everyone except them didn’t get eaten by the frogs. I mean, did we warn them that night?”
“Well, obviously we…”
“Said what? ‘You might not want to stay here in case carnivorous frogs rain from the sky?’ Even though that had never happened before?”
“Well, I don’t know exactly how…”
“And then, when it happened the first time, did everyone just say, ‘Hey, that was weird, I guess we’re lucky that only the strangers got eaten; I sure hope that doesn’t happen again in exactly ten years, but if it does, I hope that another two innocent strangers show up and get eaten AGAIN so that the horrible carnivorous frogs melt away AGAIN before they eat all of us?”
“Son, the important thing to remember is…”
“Can I get in on this? If I invite my stalkerish ex-girlfriend, or my psycho Econ prof down for a weekend, can I charge out of the house screaming and shoot them in the face and then have you tell the whole village that it only happens every five years, and that if they don’t help you bury them really quietly in the ravine without telling anyone, then I might have killed the entire town?”
“Um…”