Battle Analyzer was a program that started off as me just sniffing some packets from the wildly popular game "Pokemon X and Y". Battle Analyzer reads back to the user every pokemon chosen for the opponents team(as well as their individual values, effort values, moves, nature, and ability) as well as displays the chosen move for the given turn. After having discovered a pattern with the packets submitted after submitting a move to the other player, I decided to investigate. I noticed that the index number of the move I used(publicly available here). The only problem with this was that with moves with an index higher than 255 would report false recordings. I solved this by investigating endianess used in the packets. As a side effect, this program shutdown ranked Pokemon battling for 2.5 weeks and (arguably)forced nintendo to release the v1.2 update further encrypting all network communication.
As well as various forums posts discussing the program.
The only form of Battle Analyzer.