I don't think there's an official weapon with about 1000 to 10000 damage...probably your cousin used cheats.
Or are you talking about a new rune word?
If you look here at the official guide page you can find all that you need
![Smile](http://www.abandonia.com/vbullet/images/smilies/generic/smile)
(And you can easily see that a weapon with that exagerate damage doesn't exist)
http://www.battle.net/diablo2exp/