Help with spell required

I have in mind a spell which when casted, will create "nets", which will drop from the sky and pick up any units in a certain AoE around the caster and then pull them up into the air for a couple of seconds before dropping those units down again. I have tried making this using Impale, but I realized that if you are surrounded ( ie trapped in the middle) by enemies, you will still be unable to move out even after they fly up into the air and it also leaves the units' shadows on the ground. Is there any way to do this spell so that when the unit is lifted up into the air, units would be able to move directly across under them? Hope someone can help me, thanks in advance.

Try adding 'Amrf' to all affected units.

Could you explain in more detail how I should go about doing that?

it is crow form
by adding (and removing) it u can set a unit's fly height