Tribble

Tribbles (taxonomic classification Polygeminus grex) are small, furry animals native to planet Iota Geminorum IV. (TOS short story: "The Last Tribble")

They are notable for being as voracious eaters, as well as for their rapid rate of procreation. They are known for their affectionate nature and the calming nature of their purring. These characteristics, however, are not evident when in the presence of Klingons.

Canon

 * "The Trouble with Tribbles" (TOS episode)
 * "Trials and Tribble-ations" (DS9 episode)

Non-Canon

 * "The Last Tribble" (TOS short story)
 * "Missed" (TOS short story)
 * "Tribble in Paradise" (TNG short story)
 * "The Trouble with Borg Tribbles" (TOS short story)
 * "The Trouble with Tribals" (TOS short story)