This sounds like just another chocolate cake, but it is super moist and yummy.
1 yellow cake mix
1 small pkg instant fudge pudding
1/2 c sugar
1 tsp vanilla
1 c semi-sweet chocolate chips
3/4 c oil
3/4 c water
1 c sour cream
Mix by hand (by hand people, put your mixer away). Pour into a well greased and floured bunt pan. Bake 350* for 45-60 min. Remove from pan and pour frosting over top while it is still warm.
1 c butter
3 tsp cocoa
6 tsp milk
in a saucepan, melt butter, add cocoa and milk. Sift the powdered sugar in to avoid lumps (the recipe I have doesn't say how much to add and I've never measured, but I think about a half pound). In my experience, just when you think you've added enough sugar you probably need to add more. It should be thick enough so that it doesn't soak into the cake when you pour it over the top. If you let it cool a little it thickens up.
My sister-in-law Ashley used this recipe to make the dump truck cake with the dirt(cake) like Kim did for Wyatt's birthday and it worked really good.