This Asset has Dark Swarm in it, alone. No dummy units used, and it functions perfectly. You're free to use this spell on any unit as long as I (and Docablo and Demonette, and Kueken531, all of whom helped me make it) receive credit in your map. Enjoy! :)
Dark Swarm, if you've never played StarCraft I before, creates an AoE Swarm of Darkness that protects all units within the AoE field from ranged damage. Splash damage, spell damage, and melee damage still apply, however. It is a Zerg spell, and was on the Zerg Defiler.
EDIT: Please note that I'm going to turn this into a mod soon.
NOTICE: This map currently uses Wings of Liberty dependencies. When I manage to get my hands on a copy of Legacy of the Void, it'll be made into a MOD.