The Russian Wingmate Roc pictured here is actually a fairly common example of this, but it has also been seen on other cards as well
As a one-mana Enchantment with a meaningful enters-the-battlefield effect, the opportunity cost to play this card is quite low
It turns cards like Merfolk SecretkeeperMerfolk Secretkeeper and Fractured SanityFractured Sanity into nukes of a mill spell, and allows Altar of the BroodAltar of the Brood, Ruin CrabRuin Crab and Hedron CrabHedron Crab to be absolute menaces
It seems like there will be a better stack of payoffs for that in the future, so keep this card in mind
Set designers don't create cards specifically with Pauper in mind, but due to the dominance of Cranial Plating in that format, it was pretty much a known factor how problematic Cranial Ram would be if it were allowed to run free
The Pokemon 151 set, for example, contains Reverse Holos with a unique Poke Ball pattern highly prized by collectors