I've done a bit of testing. And While I cannot get it to OHKO, I am able to get it visible.
If you cast Mystic Storm, then a cinematic is played, the dummy unit becomes visible. It also becomes visible when trying to dig.
Until someone else gets this. There isn't much more I can do.
Unless someone who has already had this remembers what items and spells they had. Plus how they leveled their spells.