Triggered spell help(Dota like Excorsism spell)

If any of you play dota you should know about the death prophets Excorism spell which sends out multiple "ghost" that attack units when they touch and when the spell is over all the ghost come back.

Now since guinsoo portected the map I don't know how it's done, but do any of you have any idea where to start?

Btw I can use caster system functions 9.0

sounds like its locust but it returns no health

hmm ill try that ty

Actually, it's exactly the same as Locust swarm of the Crypt Lord, it also returns health; the only difference is the units used for the spell.