Avimimus was a genus of theropod dinosaur that lived in the late Cretaceous in what is now Mongolia, around 70 million years ago. Avimimus was a small dinosaur with a length of 1.5 m (5 ft). The skull was small compared to the body, though the brain and eyes were large.
A group of Avimimus that were genetically modified to possess plumage were created by Dr. Gustavus in a hidden lab in Jurassic Park. These animals were later discovered by InGen scientists Derrick Hoyle and Abby Nakajima, who had snuck into Gustavus' lab in order to find out what he was working on. Gustavus soon returned to his lab and, upon discovering the two, introduced them to some of his creations, including the Avimimus, before attempting to kill them.
After escaping from Gustavus' wrath, Derrick and Abby returned to the lab to find that all of the animals, including the Avimimus, had escaped from their cages. Gustavus soon returned, but was accidentally shot and killed by Gideon. However, the stormy weather soon caused the cliff that was holding up the lab to break and, while Derrick and Abby managed to escape, the Avimimus and all of the other genetically modified dinosaurs fell into the sea with the lab, where they drowned.