It's called SPYXX.exe and was a sample/freeware tool part of many Visual Studio versions. It is somewhat infamous. Some would argue it is famous. I don't know.

Actually, you will also need the Spyhk55.dll in order for spyxx.exe to work.

Unfortunately, I'm not sure if this tool is freeware or not. I'm not sure if it is freeware, or commercial? It was a free sample tool that came with visual studio, is all I know. So you know which exact files you need and that's all I can tell you for now.