Guided by the 12 principles of animation, stylization is a core feature of 2D animation but has been utilized mainly by experienced animators. Although there are tools tailored for stylizing 2D animations, creating stylized 3D animations remains a challenging open problem, due to the extra spatial dimension and the need for responsive actions such as timing and collision. We propose a system that helps users create stylized casual 3D animations. A layered authoring interface approach is employed to balance between ease-of-use and expressiveness. Our surface level UI is a timeline sequencer that lets users add stylization effects such as squash-and-stretch and follow-through from a preset library to stylize plain animations. Users can adjust spatial and temporal parameters to fine-tune these stylizations. These selections and edits are propagated to our node-graph-based second level UI, through which the users can create custom stylizations after they become comfortable with the surface level UI. Our system enables the stylization of not only individual object but also interactions among multiple objects like force, energy, and collision. A pilot user study has shown that our fluid layered UI design allows for both ease-of-use and expressiveness better than existing tools.