I made 2 triggers for a spell:
Custom script: set udg_Temp_Sound=CreateSound("Abilities\\Spells\\Undead\\Possession\\PossessionMissileLaunch1.wav", false, true, true, 10, 10, "DefaultEAXON")
Sound - Play Temp_Sound at 100.00% volume, attached to (Last created unit)
Sound - Destroy Temp_Sound...