Worldshaper

Worldshapers were devices used to make drastic changes on a planetary scale.

Voord Wordlshapers
The Voord used a Worldshaper, which was capable of accelerating time, to advance their evolution. Jamie McCrimmon destroyed the device and was killed in the blast. The device let out a wave that sped up time. The Voord became Cybermen and Marinus became Mondas. (COMIC: The World Shapers)

Aesirian world-shaper helmets
The Aesirians created world-shapers in the form of helmets. These devices could perform almost any change. Most Aesirian world-shapers were destroyed in the Aesirians' war with other cosmic superpowers, but Time Lords managed to preserve some in the Braxiatel Collection. Brian Carrios stole one before being fired from the collection and used it to become the most famous geohacker in history. In at least one case, on planet Campra his geohacking amounted to a genocide. The Ninth Doctor neutralised the helmet, leaving the Shadow Proclamation to decide what to do with it. A curious by-product of this incident was Jack Harkness's face on the side of one of the Eye of Orion's moons. (COMIC: Hacked)