Battle your buddies' shadow selves!
http://www.nintendoworldreport.com/news/35959
Nintendo's new sequel to the SNES Zelda title will feature StreetPass connectivity in the form of special Shadow Link battles, revealed in Nintendo Direct today.
Arranged by a kindly old man named Gramps, who at this time appears to be residing in Kakariko Village, players are able to create their own version of Shadow Link which will gain a bounty that's determined by how many hearts the player has, and which items they equip. When a player tags someone on StreetPass their Shadow Link appears at a random location in each others game worlds. Players are then able to challenge Shadow Link to battle for a chance to win their bounty in rupees.
This Shadow Link battle mode is an optional bonus feature in the game, and losing the fight will not cost a player anything.