Forced movement over time

[tml616]

Is there any GUI function that will move units a certain distance over a period of time, like the Storm Spirit's Electric Vortex spell in DotA?

I have a spell based on Thunderclap that I want to also pull units in the AoE 200 units towards the caster over 1 second. I used the "move instantly" trigger but it just doesn't suit the nature of Quicksand.