A spelldrive is a type of magical computer used to cast spells within the hard drive. Apparently, Dib owns the largest collection of spelldrives on earth. The technology made its only appearance in Gaz, Taster of Pork, and they were never mentioned or seen again, due to this episode being the third-to-last episode before cancellation.
A spelldrive is a mystical computer book that can be used to cast spells. It uses "power points" to cast the spells, and each spell uses a different number of power points. The number of maximum power points a spelldrive can contain appears to be three. If there is a way to recharge the spelldrive, it is either unknown to Dib, or he lacks the ability to do so.
The user of a spelldrive does not need any specialized mystical knowledge to perform the spells, as the spelldrive does the casting itself.
When closed, the spelldrive resembles a thick hardcover book with strange symbols on the cover. However, when it is opened, a spelldrive can best be described as a type of laptop.
The number of spells that each spelldrive can hold is unknown. However, the one Dib used to curse Gaz had at least five. Those five include Head Shrinking, Head Growing, Evil Eye, Berzerker, and Sense of the Shadowhog. It was, however, implied by the showing of the clock while Dib browsed, that the spelldrive contains many other spells, possibly thousands.