In a large bowl, combine pancake mix, cocoa and sugar. In another bowl, beat egg, milk and oil; stir into dry ingredients until almost smooth. Stir in marshmallows and pecans.
Pour batter by 1/4 cupfuls onto a lightly greased hot griddle; turn when bubbles form on top of pancakes. Cook until second side is golden brown. Top with ice cream and syrup. Sprinkle with pecans if desired.