unspeakable

The natural assumption here is that “this” refers to some unspeakable act of cannibalistic savagery in the past.

"We are devastated by this unspeakable tragedy and hold the victims' families closely in our hearts."

"We are devastated by this unspeakable tragedy and hold the victims' families closely in our hearts. We will continue to monitor the situation and will release more information as it becomes available."

By the time she realised what was happening, the fast-moving attacker had already done unspeakable damage.

In the vineyards of Bordeaux, the unspeakable has become the drinkable.