5 Shadow of the Enemy Yes, Shadow of the Enemy requires a lot of mana to make work, but there are plenty of ways to get a lot of mana even in Tales of Middle-earth (Smaug would like to give you 14 treasure tokens, just as an example)
Undo allowed you to completely break the symmetry of the format: you would play a turn three 2/2, your opponent would play a turn three 2/2
matte back protects the art fully
And in fitting with their role as robots in disguise, these powerful mythic rares will be found not in their own precons or Secret Lairs, but in packs right alongside normal, Standard-legal Brothers War cards
This card has some value, especially in Limited and Penny formats
Or in the world of Lorcana, when to throw down a Maleficent, or when to conjure a romantic ballad