How do I Make Shadow Caster opacity grow gradually?

Hello!

I use a shadowcaster behavior and i want it to cast its shadow only when i click, preferably would be to make the shadow bigger as i click it to full and then the oposite to take place as i leave from my mouse.

Consider like a have a card that when i click it it start to hover and so the shadow grows a bit in the begging from zero.

Thank you for your time!

Well i found how to make it cast shadow on drag and stop casting on stoping drag, now if i could think a way to make the shadow gradually grow on start drag and the oposite on stoping drag