2D Character, change sprite upon collision with a box trigger?

My problem is, I am trying to get it where when my 2D sprite goes over a box trigger (although if there’s someone special for 2D id like to know what that is) change the flip book from what ever it is currently for example. Idle, Running or falling. To a death flip book which i have already made. Think of it as this if i die the sprite will change to the death flip book and stay on that for lets say 2 seconds before re spawning.

I’m sorry if its hard to understand but i tried to explain best I could thank you.

Also how can you get 2d shadows like this –