How Do I Make This Mover?

[Darkness-4ever]

I pretty much want to create a mover for my projectile that when initially fired, it slowly comes out for about a half a second, then immediately accelerates to its maximum speed to the point it was launched at.

 

[mrzwach]

Look at the Raven's Seeker Missile. It has a mover which makes it move slowly at first, then accelerate when it gets within a certain range.

Try using that as a reference to create your own mover that does the same thing but accelerates sooner.