Amiibo

Amiibo are NFC figures made by Nintendo, used in games in different forms (different in each game). It can be used with the New3DS and the Old3DS with an IR peripheral.

Technical specifications

See also here.

Specifications can be found on this image, which is a compilation of screenshots made by scanning a Samus amiibo with the Android App "NFC TagInfo":

Most of the NFC pages are encrypted. This includes the actual Mii data for the owner, an UTF-16 string for the Amiibo nickname, etc.