In a medium saucepan, combine sugar, tapioca, milk and egg. Let stand for 5 minutes.
Add cinnamon and chocolate to saucepan and cook over medium heat until pudding comes to a full boil, stirring continually to prevent burning.
Remove from heat and stir in vanilla and rum.
Cool for 20 minutes. Stir for creamy texture.
Serve warm or chilled.
