Universal-based Illumination Entertainment will create a 3-D animated feature based on “Flanimals,” a children’s book series by Ricky Gervais. Gervais will voice the lead character, and the script will be written by Matt Selman (“The Simpsons”). The four-volume series, illustrated by Rob Steen, encompasses a world inhabited by 50 species of creatures so ugly and misshapen they become cute and endearing. Gervais’ character, a pudgy, perspiring purple creature, goes on a mission to change the world. “It will be great to play a short, fat, sweaty loser for a change,” Gervais said. “A real stretch.”