It basically put the opponent into your own state & makes them vulnerable, I haven't studied this one thoroughly yet but some of my friends use this code to counter other cheap chars.
Hitoverrides only override attacks but it doesnt override states. But I guess in the past, Nightmare was strong since people only knew about HitOverrides
I meant arcadboy, I kinda like the way nightmare came out, it is broli, so he should be a little cheap. after all in the DBZ series, no one could beat him one-on-one.