This is just a shorthand, terrifying way of saying, "You should be way more scared of everything, because the worst thing you can imagine is not as bad as the things you can't imagine but are very real and possibly very nearby to you in space or time, and the longer you don't know what they are, the closer they come." Or is that just the way my brain works
When Kathril, Aspect Warper enters the battlefield, put a flying counter on any creature you control if a creature card in your graveyard has flying
Creature - Giant Color tag templates(None) Graveyard Marshal , Exile a creature card from your graveyard: Create a tapped 2/2 black Zombie creature token
For each card knocked off that library, put it into its owners graveyard and Nerf War deals damage to that player
As such, the best practice is to avoid making investment decisions until the leaks are officially verified by WotC or WotC-approved channels