The Narn Bat Squad is an internet meme used primarily on the internet and USENET in discussions within science fiction fandom to illustrate (and retaliate against) writers who make bad puns. The Squad, named after the Narn race on the television series Babylon 5, is a creation of Babylon 5 creator J. Michael Straczynski.
Origins Straczynski, who has frequently participated in discussions with fans on various internet message boards and newsgroups since at least 1985, was taking part in a conversation about the Babylon 5 episode TKO. The episode quickly became infamous for the brief appearance of a sign advertising the once-popular alcoholic beverage Zima. Contrary to what was immediately thought by most fans, the sign was not product placement - in fact, it was a complicated in-joke by the Babylon 5 production crew. Straczynski had thought that the concept of Zima lasting until 1994, when the episode aired, was "hysterical;" the concept of it lasting until 2258, when the episode took place, was hugely entertaining.
In reference to Zima's frequent use of the letter Z from their advertising campaigns at the time, in a post on USENET newsgroup rec.arts.sf.tv.babylon5 made July 27, 1994, Straczynski wrote "I keep fighting the urge to have some guy show up on B5, 'Zo then I zays to him, nize ztation'...and five Narns just jump on him and beat the shit out of him, WHAMWHAMWHAMWHAMWHAM!"
Fans immediately latched on to the concept, and combining it with past posts by Straczynski, dubbed the group of Narns the Narn Bat Squad, or NBS.
Uses Beginning on the Babylon 5 newsgroups and spreading to other science fiction newsgroups and internet forums, whenever someone posted a bad joke, and, more importantly, atrocious puns that would elicit groans from the reader, the Narn Bat Squad would suddenly appear. Another user would post a follow-up, usually containing the following elements: There would be a knock on the "door," sometimes preceded by the sound of marching boots ("TrampTrampTrampTrampTrampTrampTramp") or the blow of a whistle. Once the "door" was opened, the NBS would "assault" the victim with the characteristic "WHAMWHAMWHAMWHAMWHAMWHAMWHAM!"
Soon enough, the users who made the bad jokes would begin to sic the NBS on themselves. After making an intentionally awful joke, users would end their posts by either getting "assaulted" by the NBS, or on the verge of the "assault" ("Wait - someone's at the door"). Details would soon be added by fandom, such as the NBS's penchant for Louisville Sluggers.
The reference is still common on Babylon 5 message boards, and is a frequently pointed to in-joke amongst fans of the show.
The term has also been adopted by the 'Babylon 5' based tabletop wargame, 'A Call to Arms' to describe a Narn force consisting of a swarm of heavily armed and cheap ships, generally, Ka'Tans or Ka'Tocs. The strategy has taken on the 'NBS' moniker primarily due the fact the force relies on numerous similar 'Narns' to deal its damage to one target, and due to its extreme effectiveness.