Loop Graphic With Ability Trigger

Okay so I'd imagine the trigger would be something like this:

Events - Unit Starts the Effect of an Ability
Condition - Ability Being Casted is equal to <Spell>
Action - ????

I'm not very fimiliar with the animation triggers... what would I use to get the stampede missle explosion effect (blood) to loop throughout the duration of the spell?

Special Effect triggers rather.. how would I make it loop until the effect wore off??

Doing something like this would actually require two seperate triggers and one variable
Unit variable = casterUnit
Trigger 1
Event-Unit casts an ability
Condition-Ability being cast equal to <spell>
(Casting Unit) is in units of type (<the hero with the spell>)
Action-Set casterUnit equal to (castingUnit)
TurnOn(Trigger2)
Wait <however long you want it to last>
TurnOff(Trigger2)

Trigger2
Event-Every 1.3 seconds
Conditions
Actions-Create special effect (Abilities\Spells\Other\Stampede\StampedeMissileDeath.mdx) on (chest or origin I assume you will want) of (casterUnit)

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