The card was errata'd in 2017 (a massive 15 years after the card was first printed) with the introduction of Link Monsters to the game, but prior to then, the effect of Darkness Approaches was to flip a monster face-down without changing its battle position
Its not even a very good sewing job, as the eyes and mouth remain mostly open, meaning that the objective here was more about achieving the utmost cruelty, less about actually preventing the person to see or speak
Venerated Rotpriest Venerated Rotpriest distributes poison counters to opponents like hotcakes
With trample, infect, and indestructible, Blightsteel Colossus is either always pushing poison counters through or is taking out multiple creatures a turn to stop it
Historic Horizons utilizes its digital-only nature beyond these three recurring mechanics as well, with WotC saying it makes it possible to print cards with rules that wouldnt fit in a paper frame