Problem with ability

[Drain Pipe]

Im trying to make an ablity based off my water elemental hero where it looks like he turns into a puddle and every unit that walks on him gets scewered. Anyways, i figured outhow to get him to look like a puddle, and i wanted to used the terrain deformations, with the ripples, to make them look like spikes, however, it doesn't work properly and the terrain deforemations go right through the unit. Does anyone know how i can make this skill work properly, with terrain deformations? What i wnat is for it to look like a puddle of water that has spikes that are emerging randomly around the area.