The Soft Weapon
"The Soft Weapon" is a short story written by Larry Niven that took place within his own  universe, which was first published in the  issue of the science fiction magazine  and republished in Niven's collection of stories . In , the story was adapted for the Star Trek in the form of the  episode . 

The events of "The Slaver Weapon" were later referenced, and the Kzinti themselves return, in the Star Trek comic strip story arc "The Wristwatch Plantation" (which was co-written by Niven).

Adaptation for Star Trek 

David Gerrold recalled how Niven came to write "The Slaver Weapon"; "By then, [story editor] Dorothy ["D.C."] Fontana knew Larry Niven, and so when it was time to do the animated Star Trek, she was a BIG fan of Larry's, and said, 'Gee, I'd love to get a Larry Niven story, could we adapt one of your stories, Larry?' And that's when the deal was made."  Fontana herself said, "I thought bringing Larry Niven in was a good move, again to have that connection to the science fiction community. He was the one person who had an almost perfect story for us." () 

Following D.C. Fontana's invite to write for the animated Star Trek, Larry Niven proposed two plot ideas that went undeveloped, as both had content that was deemed to be too problematic for the series. Shortly thereafter, Niven and Fontana were spending part of an afternoon at Gene Roddenberry's residence when Roddenberry suggested that Niven rewrite "The Soft Weapon" as an episode. (Playgrounds of the Mind) Fontana reflected, "We told Larry, 'Just write it, but put in our characters. You can put in the Kzin and all that." () In retrospect, Niven remarked of the adaptation idea, "That worked." However, he was initially not entirely sold on the prospect of including in the episode the Kzinti, who feature in the original short story as well as elsewhere in the Known Space universe. "I thought hard before giving the Kzinti to the Star Trek universe," Niven acknowledged. "I did it because I thought it would be fun to see what others would do with them." ()

Differences from the original story 
Some changes were evidently made between "The Soft Weapon" and this adaptation. 

Most notably, Niven did not have to include all the series' main characters in this episode. For instance, he noted, "I was given permission to leave Kirk out." (Playgrounds of the Mind)

The main characters in the original short story were: 
 Jason Papandreou, a Earther, was a veteran gunner of the last stages of "the last kzinti war", who was written to be portrayed as Lt. Sulu;
 Anne-Marie, Jason's Jinxian wife, who was written to be portrayed as Lt. Uhura;
 Nessus, a Pierson's Puppeteer, was a manic-depressive pacifistic herbivore, who was written to be  portrayed by Spock.

In the original story, the Papandreou piloted the Court Jester, which became the . The ship was en route "home" to Jinx, rather than Starbase 25. 

The visit and encounter near the star Beta Lyrae remained unchanged. The region was last visited by Papandreou near the end of the last Kzinti war, which themselves ended "decades" earlier, and was not officially over. This was in contrast to the Sulu's reference of the wars ending "two hundred years ago". 

Although Chuft-Captain and the Kzinti Telepath are the only crew members from the Traitor's Claw who receive a name or designation here, the original short story names the other members of the vessel's crew as Flyer (who later carries Telepath), and Slaverstudent (who opens the box). 

The police web was also an element of the original work, however, it was utilized aboard the hero ship, Court Jester, rather than the enemy ship, Traitor's Claw. 

Stasis boxes were used by both the Slavers and the tnuctipun (who were only alluded to in the episode as "their subjects"). Previous stasis boxes were originally said to contain Slaver weapons, which included "the variable-sword" in one, and "the disintegrator" in another; whereas in the episode, it was stated that a flying belt was found in one, and a disruptor bomb in another. 

The new box, which actually belonged to a tnuctipun (rather than simply "an espionage agent"), contained in the original:
 A bubble tool, which became the Slaver weapon;
 A cube of raw meat, which was was still meat;
 A severed hand, which became a photograph of a Slaver.

External links 
 , original short story
 
 

Production material