We were introduced to tribbles in the 1967 Star Trek episode "The Trouble with Tribbles." They were small, furry aliens that didn't do much of anything besides reproduce abundantly until they were in every nook and cranny of the USS Enterprise. Tribbles have made encore appearances in other Star Trek series and are now a permanent and somewhat comedic part of Star Trek lore.
But now a new comic book looks further into tribbles. IDW’s Star Trek #500 comic book revisits the tribbles and the ST:TOS crew in a story written by Jordan Blum and Patton Oswalt called “I Knew You Were Tribble When You Walked In.” It retells the tale of that first visit to the Enterprise ...from the point of view of the tribbles themselves. It's a bit shocking to think of tribbles as sentient at all, since we considered them a form of wildlife- an invasive species, actually. But here we learn about their thoughts and the way they communicate with each other. Spoiler- one of them has a crush on Captain Kirk. Read about the inner lives of tribbles in a review at Inverse.