From the archives of TiPWiki, the unofficial Duke TIP Wiki
Grapism is the religion that celebrates the almighty grape, Thanos. Many grapist take surgery to turn into a mortal version of him, i.e. Christian
What the difference
Let me refer that this form of grapism and the grapist of this religion aren't grape rapist, or gay rapist. They are people who worship grapes and Thanos.