using a summon-strike-animate dead spell

[TheAncient]

ok. for my map i have two spells. death coil(no duh it started with it.) but i want a trigger for when a unit dies from the death coil, that it automatically turns into an animated dead version. when i tried i had to give the death knight animate dead so that it casts it right after killing with death coil, but that isnt how i wanted it at all.

also for his ultimate he summons 6 voidwalkers which i want to select different targets, and that the targets they selected are banished (wihtout the voidwalker casting the spell) and that the voidwalker then uses death coil on the banished unit. and like before the unit dies and becomes animated dead. i dont want it to affect heros. (the animated dead part. the rest can hit them)

im fairly decent with triggers but i cant figure this out.

 

[TheAncient]

so the dummy is meant to be the one to cast the spell?

 

[Need_O2]

Yes .