Flik is a nerdy, inventive ant who wants to make a difference to his colony's way of life, but has a tendency to make things worse in the process. His inventions include a telescope created by wrapping a blade of grass around a dew drop; an automatic harvester; several items of traveler's gear; and the bird-shaped aircraft used to terrify the grasshoppers. He is friends with Dot, the Circus Bugs, and the Blueberries.
In the film, Flik is an odd, inventive ant who is desperate to make a difference to his colony's way of life. He is also sweet to Princess Attaand has a crush on her, but has a tendency of making things worse for himself. He does this by accidentally destroying the pile of food for the grasshoppers, and then causing the leader, Hopper, to double the offering that has to be completed by the end of autumn. During his trial, the royal council reprimands him with Atta sentencing Flik to dig in the tunnels for one month, but Flik suggests recruiting "bigger bugs" to help fight the grasshoppers away.
After the royal council approves his idea (assuming that Flik would not be around to cause any more trouble), Flik leaves Ant Island and ventures to the city (rubbish under a caravan), where he mistakes a recently fired circus troupe for warriors when some of them do an act based on Robin Hood. After Flik returns to Ant Island with the circus troupe, he introduces the ants to the troupe, but the troupe refuses to believe the reason Flik has recruited them and fly across the stream from the Ant Island, with Flik in pursuit. After a nearly fatal encounter with a bird in which Dot, Atta's little sister, is saved by the circus bugs, Flik is given the privilege to speak with Atta herself, in which Atta apologizes to Flik for her misjudgment.
Learning from Atta that Hopper is afraid of birds, Flik comes up with an idea and tell the circus bugs that they will build a makeshift bird, controlled from the inside, to scare Hopper away, as long as they keep the idea secret from the rest of the colony. The idea goes into motion and, during the process, Flik is shown acting awkwardly around Atta and staring lovingly at her. After the bird is complete, the ants celebrate and Atta thanks Flik for finding the "warrior bugs," getting their antennas tangled. But when the circus troupe's leader,P.T. Flea, arrives at the island in search for them, Flik's mistake is made public to the colony. An upset Atta sees Flik through his lies and regrettably has him banished, this time for good. Downhearted, Flik leaves Ant Island with the circus troupe.
However, Dot catches up with him, and tells him that Hopper, who invaded the island with his grasshoppers, will kill her mother, the Queen, after they have finished gathering food. Flik is still upset with what he has done to the colony and does not want to do anything, but when Dot brings him a rock and uses Flik's words from the beginning from the film, Flik regains his confidence and returns with the circus bugs to Ant Island, where he, Dot, and the Blueberries climb aboard the "bird" and take control the model. The plan almost works, but the "bird" misdirects and crashes into the circus wagon, freeing P.T., who sees the "bird" and sets it on fire, prompting Flik to crash-land the "bird."
Hopper, realizing that he has been tricked, hires his henchmanThumper to savagely torture Flik when Flik confesses that he is responsible for the mayhem. Despite the injuries he has sustained, in the film's turning point, Flik angrily stands up to Hopper, exposes his plot to kill the Queen, and states how ants are not meant to serve grasshoppers, but are awesome creatures who are strong in number. Flik's speech astonishes every ant in the colony, including Princess Atta, as the ants realize what Hopper is putting them up to. As Hopper beats Flik up again, Atta rushes in to stop him, tells him to leave, and helps Flik up, commending him for his bravery.
Inspired by Flik's speech, the ants charge at Hopper's gang and scares the grasshoppers away. Flik and the other ants seize Hopper and shove him into the circus cannon, but the rain falls, prompting the ants to run for it, but Flik is still injured and collapses while running. As Atta rushes over to help Flik up, a humiliated and vengeful Hopper then pops out of the cannon and takes Flik hostage as he flies away. The circus bugs attempts to give chase, but are unable to do so as they end up being stuck in a tree. However, Flik is rescued by Atta, whom he instructs her to take him across the stream to the other side where he has previously encountered the bird. As Atta watches worriedly, Flik faces Hopper, who backs him to the bird's nest and chokes him. As the bird picks up Hopper in its beak, Atta quickly pulls Flik to safety, and they cringe as the bird lowers Hopper into the beaks of its chicks and ending his reign of terror and insult on the ant colony.
When spring comes, the circus bugs prepare to leave, and P.T. Flea who accidentally aided Hopper and been severly punished for his actions asks Flik if he is sure he can't come on a tour with them, to which Flik answers that he belongs to the island, as well as with Atta, who has since made up with him. The circus bugs thank Flik and, along with the ants, applaud at him for his heroism and intelligence. Atta then approaches Flik and kisses him, choosing him as her mate. Flik then rushes over to help Heimlich, who has emerged out of a cocoon, still a caterpillar, but now with small butterfly wings, into the air. As Flik waves good-bye to his friends, he is taken to a tree root by Dot and Atta for a better view.
Flik makes an appearance with Heimlich in the blooper reel for Toy Story 2, where he's excited about shooting onA Bug's Life 2 before being informed by Heimlich that he's in a sequel, but not for their movie. They are then blown off a branch they're standing on by Buzz Lightyear's karate chop.
- Flik met Winnie the Pooh and his friends in Pooh's Adventures of A Bug's Life.
- Flik will meet Littlefoot, Ash Ketchum, Stan Marsh, Woody, and their friends in Littlefoot's Adventures of A Bug's Life.
- Flik will meet Timon and Pumbaa in Timon and Pumbaa's Adventures of A Bug's Life.
- Flik will meet the FT Squad in The FT Squad's Adventures in A Bug's Life.
- Flik will meet Bloom and her friends in Bloom's Adventures of A Bug's Life.