The Eel by Miriam Allen DeFord

He was intimately and unfavorably known everywhere in the Galaxy, but with special virulence on eight planets in three different solar systems. He was eagerly sought on each; they all wanted to try him and punish him—in each case, by their own laws and customs. This had been going on for 26 terrestrial years, which means from minus ten to plus 280 in some of the others. The only place that didn’t want him was Earth, his native planet, where he was too smart to operate—but, of course, the Galactic Police were looking for him there too, to deliver him to the authorities of the other planets in accordance with the Interplanetary Constitution.

For all of those years, The Eel (which was his Earth monicker; elsewhere, he was known by names indicating equally squirmy and slimy life-forms) had been gayly going his way, known under a dozen different aliases, turning up suddenly here, there, everywhere, committing his gigantic depredations, and disappearing as quickly and silently when his latest enterprise had succeeded. He specialized in enormous, unprecedented thefts. It was said that he despised stealing anything under the value of 100 million terrestrial units, and most of his thefts were much larger than that.

He had no recognizable modus operandi, changing his methods with each new crime. He never left a clue. But, in bravado, he signed his name to every job: his monicker flattered him, and after each malefaction the victim—usually a government agency, a giant corporation, or one of the clan enterprises of the smaller planets—would receive a message consisting merely of the impudent depiction of a large wriggling eel.