Talk about it here.
Brian Carrios, more commonly known under the alias Taggani, was the most famous geohacker in history.
Before becoming a criminal, Carrios was an art historian working at the Braxiatel Collection. He was expelled from the Collection when he failed to spot a forgery. Before leaving, he stole an Aesirian world-shaper helmet.
He began calling himself Taggani, creating graffiti on planetary scale. In one particular case he fused a planet's seas into glass and replaced its deserts with swamps. At first, Taggani's art was harmless, but a turning point was reached when he overran the inhabited planet Campra with Argurian creepers, killing everyone.
By the time he visited the Eye of Orion, he was wanted in nine systems. Coincidentally, the Ninth Doctor, Rose Tyler, and Jack Harkness were on the Eye of Orion when he began reshaping it. They attracted his attention with the Doctor's sonic screwdriver and were transmatted onto his ship. Learning that the Doctor was a Time Lord, Taggani used his powers to read the Doctor's memories. The Doctor used the mental link to manipulate the World-Shaper into writing, "Taggani is Brian Carrios! Come and get him!", onto the surface of the Eye of Orion. This attracted the attention of the Shadow Proclamation, who arrested Taganni. (COMIC: Hacked)