is it possible to customize shadow trailing to other shape?

[msyazreen]

hi, i want to change the arrow (shadow) to black dot with transparency (without changing main arrow). is it possible? currently in documentation only can adjust with simple css. (grayscale(10%) opacity(5%))

layerView.featureEffect = new FeatureEffect({

  filter: new FeatureFilter({

    //where: "speed > 0",

    timeExtent: timeSlider.timeExtent,

    geometry: view.extent

  }),

  excludedEffect: "grayscale(10%) opacity(5%)",

});