P.T. appears for the first time when the spectators leave, disappointed with the show. He begs them to come back and runs away from a fly asking to be reimbursed. Then he urges the Circus Bugs to go on stage but the audience gets bored and laughs at them. Desperate, P.T. invents the Flaming Death which commands attention but ends up falling victim to the number and is set on fire. Very annoyed, he fires the insects.
Later, P.T. goes to Ant Island to find his troop. He tells them that Flaming Death has caused quite a stir and reveals that the Circus Bugs are not true warriors. This leads to Flik being banned for lying to the ants and leaves with P.T. and the circus. On the way, the chip hums, happy to get rich. When Flik decides to return to rescue Hopper's captive ants, Rosie ties up P.T. and lock him in the wagon.
When Flik puts his plan into action with the fake bird, he crashes into the circus carts and accidentally releases P.T. The latter is horrified to see the injured insects, as they pretend, and burns the model of the bird, ruining Flik's plan a second time and allowing Hopper to order Thumper to beat Flik. However, he realizes his mistake that he aid Hopper and is present during Hopper's capture.
At the end of the film, a redeemed P.T. recruits Molt, Hopper's brother, and leaves the island with the Circus Bugs.
P.T. Flea is a brown flea with spikes on him, a black hat, brown eyes and a twig in his mouth.
P.T. Flea acts stingy and self-absorbed and he loves money. He started off as an antagonist, but in the end, he reforms.
P.T. Flea was named after the co-founder of Ringling Bros. and Bailey Circus, P.T. Barnum.
John Ratzenberger states that P.T. Flea was his favorite Pixar role.
P.T. Fleas was only the good guy who helped the villains and almost beat Flik by mistake and error.