Guys apparently you can find out what's the Surprise Feature on your own if you had an IQ of monkey but sadly this wont happen so a guide is a must have.
here is what Garyopa just said regarding the Surprise Feature:
Here's my guess for the surprise feature(btw totally a guess)
With the right button press(s)/start up procedure, the card can be dropped into a "crippled" sky3ds like mode( basically just a clone/copy of a retail card) which will work on ANY 3ds/2ds official system NAND version.