"A Toad, a Wistful Toad, with Jewels in Its Head"

"The Witness."
By Eric Frank Russell (1905-78).
First appearance: Other Worlds, September 1951.
Reprinted multiple times (HERE).
Short story (20 pages).
Online at Archive.org (HERE).

"The eyes of the world were focused on the courtroom where the monster from space was on trial. The Prosecutor had an air-tight case built on the testimony of sixteen witnesses, while the Defense—well, they did manage to find one witness!"

Unexpected guests can be an unwelcome surprise, a strain on one's hospitality, but what if they're from another planet . . .

Typo: "an you detect"

Resources:
- Information about Eric Frank Russell isn't hard to come by on the Internet; see (HERE), (HERE), (HERE), (HERE), and (HERE).

- You can read about Procyon (about 67 trillion miles from here) in fact (HERE) and fiction (HERE).
- In science fiction aliens come in all shapes, sizes, sexes, and psychologies; see Winchell Chung's plush Atomic Rockets webpage on "Aliens" (HERE). After reading the story, you can decide which type of alien, as defined below, that Russell has made Maeth, our protagonist:

"ALIENS. Intelligent races who are not EARTH HUMANS. The term as such is never used for non-intelligent species, however unearthly, though in TECH-JARGON these may be called Alien Life Forms. Nor is it used for Earth Humans who must register with the immigration service. In general, Aliens fall into two distinct groups, REALLY ALIENS and ALIENS WITH FOREHEAD RIDGES." — Rick Robinson, The Tough Guide to the Known Galaxy (HERE)

The bottom line: "My folks came to the U.S. as immigrants, aliens, and became citizens. I was born in Boston, a citizen, went to Hollywood and became an alien."
— Leonard Nimoy