SF STORY PREMISE:

SETI program decodes an alien signal clearly targeting us.

Hi! We see you're still facing the Great Filter! We want to help! Based on your anatomy per broadcasts we decoded, here is a blueprint for a device that will solve your problem!

Humans: decode blueprint.

It's for an improved guillotine.

@cstross Fantasy story premise. A wizard casts a spell such that each week (day?) the richest person in the world dies. (It's magic, it can work out what that means and who that is.) And then ... ?

@dearlove Ideally the spell does it deniably, eg. by giving them an aneurysm or an unfortunate fall from a Moscow apartment window or something not obviously magically-induced. At one per day, in one week we could get rid of Elon Musk, Larry Ellison, Jeff Bezos, Bill Gates, and quite probably Vladimir Putin and a couple of other deplorables. I'd call that a job well done!

The snag is, what if the spell has no termination clause and keeps going. After a few years we run out of billionaires …

Then you have to tune its frequency to billionaires.