Ground Seal

The cantrip is the whole reason this design has aged the way it has: most hosers that shut off a strategy sit dead in hand when the opponent isn't playing it, but a graveyard answer that replaces itself the instant it resolves can ride in any maindeck as a hedge without costing you tempo or a draw. The protection it grants is narrow and surgical, and that precision is the point. It does not exile graveyards or stop recursion outright; it only severs the line between a spell or ability and a target in the bin. So it blanks Recurring Nightmare and the reanimation effects that name a specific creature in a graveyard, along with anything that explicitly targets a card there to retrieve or interact with it. What it leaves untouched is just as deliberate, and the operative word is "target": delve, threshold, and flashback don't target cards in the yard to function, so they slip right past it, as does anything that merely counts graveyard size or returns cards without targeting. That distinction matters most when the enchantment is protecting your own graveyard, since the things you actually want to do (delving, exiling for flashback, fueling threshold) never name a target and keep working. A scalpel where most graveyard answers are hammers, and one you never feel bad about drawing.