So, one of my favorite cards from Eldritch Moon was always Permeating Mass. Sure, its difficult to use, but you can’t deny its powerful. Actually very powerful. The problem is that its risky. If the Mass gets going, you’ll just lose all your own creatures as well.
Unless, their somehow protected from it. For example, in my EMN Prerelease deck I had a Permeating Mass and I played it happily, because I also had Voldaren Pariah and two Ishkanah, Grafwidows, who could do damage without having to enter into combat with all that Mass.