They're basically uncounterable and they can't be interacted with in most situations
Ideally we can respond to opposing plays by activating a looter, discarding a creature with a relevant effect, and immediately putting that into play to fizzle their plans
Tekuthal, Inquiry Dominus is pretty restrictive as doublers go since only a narrow range of decks care enough about proliferation to support it, but the horror does a great job where it matters and becomes awfully hard to remove thanks to the activated ability
Common Uncommons Enlarging the difference between the opening experience more between these products is the ghastly repetitive nature of the uncommon cards
Maybe WotC was nervous about potential leaks, since they'd have to present those Final Fantasy cards to different parties ahead of time, but whatever the reason, the whole Commander set has been revealed weeks before the main set's full spoiler
This type of error is usually very common