Ukagaka (伺か), Nanika (何か), Sakura (さくら), Nin'i-tan (任意たん) or Nise-Haruna (偽春菜) is a catch-all term for Japanese software which shares a single format and function: to provide a pair of mascot characters for the user’s computer desktop. These mascot characters can perform some useful functions such as checking e-mail or adjusting the clock of the computer, but are most popular as an aesthetic add-on, which “says” weird things.
Wikipedia