Camouflage Skill

I need to make a skill for a unit called Camouflage

It needs to be like hide but not auto activate and work during the how can I do this?

Base it off Windwalk?

but then they can Move, I guess I forgot about mentioning that. If they move it should break

A unit casts hide
create 1 dummyunit
order dummy unit to cast invis on triggering unit
remove dummy unit
order triggering unit to hold position
wait until order of triggering unit not equal to hold position, checking every .1 seconds
remove buff by type (invis)

Where "hide" is a dummy spell with no target, not the shadowmeld ability. Since he said he didn't want it to auto-hide.