Prepare cake mix according to directions and pour into cake pan.
In a small separate bowl, mix cream cheese, sugar, and egg until smooth.
Drop cream cheese mixture by tablespoon fulls onto top of cake.
Marble cream cheese throughout cake mix.
Sprinkle peanut butter chips over top of marbled cake.
Bake in a 350 degree preheated oven for 35 to 45 minutes. May take longer depending on oven. Make sure when testing with tooth pick that you insert the toothpick into choc. cake and it comes out clean and dry. (Inserting toothpick into cream cheese will leave a wet look on the toothpick and may cause you to think cake is not done and you will over bake the cake.)