Fear appears to be patterned after Goofy in that he is tall, lanky, clumsy and, well, fearful. His role is to alert Riley of every possible hazard that she might run into. While Disgust may not be impressed with the "cool" girls at school, Fear see's them as strangers that should be avoided.
Fear is played by the animated Bill Hader known for his many years on Saturday Night Live. In addition to his acting roles in You, Me and Dupree, Hot Rod and The Disappearance of Eleanor Rigby, he too has an extensive voice acting credits to his name including Hoodwinked Too! Hood vs. Evil where he played Hansel to Amy Poehler's Grettel. He has also voiced characters for Cloudy with a Chance of Meatballs, Monsters University and will have a lead role in the upcoming Disney-Pixar flick, The Good Dinosaur.