Looking at Hunted Nightmare's stats and mana cost alone will make you want to draft it immediately. Though Nightmare allows your opponents to put a deathtouch counter on one of its creatures, you can use this to your advantage.
It is possible that your opponent won't have any creatures by turn three when you cast Hunted Nightmare. But if there is a creature, Hunted Nightmare has Menace, which protects it from being blocked by that creature.
This is undoubtedly one of the best rare choices for Limited.