DSLite: What is this thing?

Pic of the accessory.

Ok, so I just went searching around my house for a while and found a black cartridge-like thingy that fits in my DSLites GBA slot. I have no idea what it's for, but it has a little electronic part showing at the opposite end. I check the GBA thingy and it says nothing is inserted. The electronic part is surrounded by two bars or whatever, and the whole accessory is black (except at the end). I suspect I have to plug something into it?
Help would really be appreciated.
I'm just curious about it!
Also, I will give a link to a pic of it soon...



Edited 1 time(s). Last edit at 06/16/2012 11:39PM by EarlAB.

Hard to tell from that image, it's a bit small and unclear. If it doesn't show up as an accessory pack on the ds lite my first guess would be a slot 2 flashcard of some sort.