Worldshapers were devices used to make drastic changes on a planetary scale.
According to Frobisher, the Worldshapers were banned "ages ago" by his time, after a unit installed on Yxia tore the entire solar system asunder. The Voord used a Worldshaper, which was capable of accelerating time, to advance their evolution on Marinus. Jamie McCrimmon destroyed the device and was killed in the blast. The device let out a wave that sped up time and the Voord became Cybermen. (COMIC: The World Shapers) According to one account, this resulted in changing Marinus into Mondas. (COMIC: The World Shapers) However, the Twelfth Doctor stated that the Cybermen of Mondas evolved independently from those on Marinus. (TV: The Doctor Falls)
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)