Knack is a fun word to say. Try it! "Knack."
However you slice it, the upcoming PS4 game Knack now has an iOS companion app, which lets you "match three" in the style of Bejeweled to unlock new console content. As you unlock "parts," you'll be able to beam them to Knack in the PS4 game when it comes time for the console's launch.
It's highly inoffensive considering the fact that it's a free game, and it has a distinct Fable: Pub Games feel to it -- I don't really mind unlocking a few extras before a game is out, so long as they aren't gated entirely behind it.
Knack's Quest [Apple]