Apparently computer virus, worm, and Trojan horse programs are scary. That seems to be the flimsy (but amusing) premise behind this offer, anyway.
Oh, and Happy Hallowe’en! 🙂
[UPDATE] Warning! When I tried to go to that site (not the LifeHacker one, but the eWeek one listed in the LifeHacker article above), I got a Firekeeper alert about a “[script] tags GET request cross site scripting attempt” from ad.doubleclick.net. I don’t know enough about it to say whether it’s a false alarm or not — visit at your own risk.