It is one of the many milestone rewards players can earn on their account, like collecting a certain amount of different cards
Chthonian Nightmare will let us sacrifice our fodder tokens for more precious zombies, but I think the lower mana requirement for Chthonian Nightmare makes it a bit better
Since Traumatic Critique will always replace itself at worst, the card can easily two-for-one opponents for just a few extra mana
Of course, to stay alive, you also need removal, and thats where schemes like Tooth, Claw, and Tail come in
Upon completing the trade, you will receive a Pokmon exactly like the one described
If you can transform it quickly into Silverpelt Werewolf, itll be an above-rate card-generating beater, which is a great card