Preheat oven to 350 F.
Make the crust: Combine cookie crumbs and butter. Divide among 4 4-inch tart pans. Press crumbs firmly into each pan, place on a sheet pan and transfer to oven. Bake for 12-15 minutes, until cooked through. Remove from oven, prick tarts with fork and allow to cool completely.
Make the filling: Meanwhile, in a large bowl combine jell-o with milk and cayenne pepper, whisking continuously until thick and creamy. Transfer to refrigerator until ready to use.
Fill each tart with spicy chocolate pudding and top with whipped cream. In a small bowl, whisk together grapefruit juice, cherry juice, and sugar. Add red food coloring for desired hue.
Drizzle each tart with ‘blood’ and serve!