There is an easier way to do it. [Statedef -2]
[State 0, AssertSpecial]
type = AssertSpecial
trigger1 = 1
flag = invisible
[State 0, Explod]
type = Explod
trigger1 = numexplod(10) = 0
anim = 909090
{the rest of the details of the sparklies explod shall go here}
--------------------------------------------------------------------------
Or maybe:
[Statedef -2]
[State 0, Changeanim]
type = ChangeAnim
trigger1 = anim != 909090
value = 909090
But the first way seems to be better cos you can still use HitDefs (in the other ones you can't cos you will always be in anim 909090 and you won't have collision1 boxes, you will be able to hit only with helpers and projectiles)