For purposes of character animation, imagine a library of pre-defined, keyframed actions which we could trigger whenever and as often as we want simply by dropping a layer marker where we want the

This expression will increase (and animate) the rotation by the user defined number of degrees at every marker on the layer.

This script displays a count of the number of markers on the selected layer.

This script will render (actually send to the render queue) any frames that are marked by layer markers that are within the comp work area.

Apply this expression to a layer's Scale property to make it wobble at each marker.