The Pokémon on offer is Genesect; a Bug/Steel collaboration which boasts its very own exclusive move, Techno Blast (85 Damage, 100% Accuracy, 5PP. Element of attack is determined by the type of Drive the Pokémon is holding during battle). According to Bulbapedia, Genesect was revived from a 300 year old fossil, but modified by Team Plasma to become the world’s most powerful Pokémon. It is able to alter its attack types by holding different Drives.
In order to claim this bad boy, all players need to do is connect to Nintendo WiFi before November 12th. This leaves quite a hefty window of just over a month from the October 7th release date, so I’m sure lots of people will be taking advantage of this awesome offer. Too bad so far it seems to only be applicable in North America… but fingers crossed that’ll change closer to the release date.