A poll was held to determine who between Victini, Jirachi, Manaphy and Darkrai would get a special distribution as a tie-in to the Klefki short associated with movie 17. Well, Darkrai turned out to be the winner, and was given a randomly picked move that it can't learn otherwise. And this time, the dart thrown by a blindfolded Junichi Masuda hit PHANTOM FORCE! OOOOOOOOONE HUNDREEEEEED AND EEEEEEEEEEEEIGHTYYYYYYYYY!!!
What, you don't believe my story? How else could a crappy non-STABbed physical move be given to a Pokémon with 90 base attack (which would be low even by OU standards) and 135 base special attack? Oh well, it's no big deal, I think we can all agree that Darkrai definitely doesn't need another useful move. Unlike the other three. Why, oh why did Darkrai have to win?