Short story; scientists find mysterious alien man who refuses to talk to them

Question

This is a sci-fi short story I read years ago. For the life of me can't remember the title. I've had no luck on Google so far. It appeared in an anthology.

I read it around 12-15 years ago but it's definitely older than that. It might be anything from 20 to 60 years old, but I think it's more likely that it was from the '50s or '60s. The setting and the bomb theme remind me of the paranoia that permeated American society at the apex of the Cold War.

Scientists find a mysterious alien man, but he refuses to talk to them. He just smiles and acts contemptuously. When they provide him with pen and paper, he doodles some device. When they build it it explodes. It was a bomb. They had built a smaller version of it so it didn't do much damage, but it was an incredibly powerful bomb. Turns out his civilization is so advanced, and his people so much smarter than earthlings, that drawing a bomb is like drawing a kettle to him. He was toying with them. Eventually he has a seizure (he's allergic to something that is commonplace for humans, can't remember what) and dies.

Answer 1

This looks like "The Strange case of John Kingman" by Murray Leinster.

I've found an online summary:

Meadeville Mental Hospital is the oldest mental asylum in the US, "founded some years before the Republic of the United States of America." Young Dr Braden here has discovered some anomalies in the records of a may be 50 year old inmate named John Kingman: no information on his age, relatives, even date of admission. And he has 6 fingers on both hands - all perfectly developed. "understands English very slightly if at all. Does not speak."

Further investigations begin revealing incredible information: he was admitted here on "21st of May, 1786", a full 162 years ago!! He is said to be suffering from "delusions of grandeur", behaves regally around everyone else, & keeps making funny pictures & throwing them at those around him.

Admitted 162 years ago & looking like 50! That makes Dr Braden order detailed tests. What he finds is two hearts, more ribs & vertebrae than normal, normal body temperature of 105F, ... In fact, a very different internal design, though he seems to have lived well off on normal food & looks like a normal human.

The sketches he keeps handing out turn out to be designs of an X-ray machine a doctor can carry around in his pocket, an atomic power plant that uses silicon for fuel,

and this is what you remembered:

a bomb that will blow up its makers

(In turn, this reminded me of Sturgeon's Mewhu's Jet, where a very different and much friendlier alien also pops by with an incredibly advanced technology which Earthmen covet, again to no avail).