Make mesh in Blender, add skeleton with a short bone chain in the middle (yes puddings have a skeleton), weight paint, make jiggle bone in Godot, add BoneAttachment3D, add RemoteTransform3D to push transform to AnimatableBody3D with collision shape that's a bit longer at the bottom than the actual pudding (to prevent tunneling and to prevent being pushed out downward), and that's about it :-)