To achieve the effect of having an animation drawn on top of a Spine2D animation and have it follow or be affected by the Spine2D animation in After Effects, you can utilize the exported video or PNG sequence from Spine as your base layer in After Effects. Then, create your additional animation directly within After Effects on a separate layer above the Spine export. Use After Effects' tracking and parenting features to link the motion of your new animation layer to the Spine animation layer. This way, movements and transformations applied to the Spine animation can be reflected in the animation you draw on top. Remember, while you can't directly manipulate Spine's skeletal animations within After Effects, this method allows you to complement the Spine animation with additional effects or animations that move in sync with it.