To be put quite simply, this can only be used by mac users, as far as I know. If you are a PC, tough luckAlso, I'm not sure if this works with desktops, I only tried it with my laptop.
Anyways, I found out this little gem accidentally while playing WoW the other day. If you're playing WoW, and you click the little Apple symbol at the top left of the screen, and your WoW will instantly freeze... and it doesn't just freeze the screen client side and your character keeps on moving server side.
It shows the character running in the same place, and the best part is, you don't even need to download a program for you!
To recap for the lazy ones...
1. Open WoW.
2. Get on your character.
3. Click the little Apple at the top left of the screen.
There. You're done! That's it.
Hope this helps some of you, maybe in PvP to confuse enemy players, or some other way.