Mechanically, this takes the form of the manifest dread keyword action, which lets you choose one of two cards to put face down on the battlefield
Using it for mana for a few turns and then turning it into two 2/2 spiders on the next is a pretty decent proposition , and even though it has sorcery speed stapled onto that effect, it's something for ramp decks to do when their draw is too many acceleration cards and no payoffs
Tap it, target a zombie, and suddenly your deck feels like it has an endless supply of threats
They all look powerful enough to be fun without being so oppressive as to become teeth-grinding
But its also by far the most risky and fair of Magic s S-tier mechanics, leading unwary players into collapses just as spectacular as the victories it can produce in expert hands
Slight deviations might mean the card is a miscut or a fake