Use Percent Damaged = 100, then Set Animation with nothing in the box, both on the unit. It's a trick to interact with the unit even after it has died. Once it's dead you can use things like damage unit -1, change unit type, with conditions such as unit's in los, or units in area. If you want the exact effect you need to do it with modding, but this is the closest you can get with triggers. If you want more info let me know.