Peanut Butter Mousse Pie

In a small saucepan over low heat, cook chocolate chips and oil until chocolate melts (do not burn). Remove from heat; set aside. In another small saucepan, mix gelatin and water; let stand for 1 minute. Stir over low heat until gelatin dissolves. Remove from heat; set aside. In a large mixer bowl at medium-high speed, beat cream cheese, sugar, sour cream, peanut butter and vanilla until fluffy. Gradually beat in gelatin mixture. Place bowl of peanut butter mixture in a larger bowl which contains cold water and ice. Stir peanut butter mixture until it mounds when dropped from a spoon. Remove bowl from ice water. Fold in whipped topping. Mound into pie crust, making a swirl in the center. Pipe or drizzle with reserved chocolate mixture. Chill overnight to develop flavor before serving.