Minecraftia

Minecraftia was a cubic planet whose surface was somehow identical to the Earth-based virtual game Minecraft. Christel Dee crashed there while misusing the Doctor's TARDIS. (WC: Doctor Who Minecraft)

Features
The TARDIS scanner identified Minecraftia as a planet with breathable oxygen levels in its atmosphere, reasonable gravity, and no radiation, making it hospitable to human life. From space, it appeared as a pinkish cube. (WC: Doctor Who Minecraft)

History
Due to a chronon link, the Doctor's TARDIS's architectural reconfiguration system reacted to a Minecraft-themed desktop theme being uploaded to its databanks by creating a temporal chameleon arch around its pilot. This meant that when Christel Dee entered the TARDIS, she found herself forced into Minecraft-like dimensions; not only did her body now resemble a Minecraft sprite version of the Tenth Doctor, but she followed Minecraft "rules".

Unfamiliar with this situation, Christel misused the telepathic circuits and eventually crashed the TARDIS on Minecraftia, which she initially believed to be an ordinary planet. Upon venturing out, she first inexplicably found the Capitol (which should have been on Gallifrey) and then realised the truth: she was, somehow, insie the Doctor Who-based Minecraft rollercoaster built by two acquaintances of hers, Nuro and River. She was able to physically interact with the Minecraft avatars of the two, who did not realise anything was amiss, and chatted with them about their rollercoaster project. She then left aboard the TARDIS. (WC: Doctor Who Minecraft)