Qurunx

The Qurunx were creatures of sentient energy, described by the Thirteenth Doctor as "One of the great mysteries of the universe", "rare", and "enough to power planets and civilisations". They resembled large ethereal jellyfish, with long thin tendrils glowing with blue and orange light. They utilised consciousness shields as a defence, being able to disguise themselves to the observer as something that they instinctively want to protect, such as a child, The energy they produced could also be channeled into a weapon capable of disintegrating planets.

One Qurunx, being transported by a "Space Train" of the Toraji Transport Network had been taken by the CyberMasters and tethered to an metal cyber-conversion planet surrounding Earth, powering it in the process. It was hidden with a "rudimentary cloaking shield". To the Thirteenth Doctor and Yasmin Khan it appeared as a young humanoid child, due to a consciousness shield. This was until the the Doctor disabled it, revealing the true Qurunx form. Once freed, it was ordered by the Thirteenth Doctor to "disintegrate everything" but it was temporarily diverted into attacking her instead by the Master, leading to her regeneration. It succeeded in (TV: The Power of the Doctor)

It is unclear whether the "Toraji Transport Network was intended as a reference to the similarly named Torajii Star and System, due to the slightly different spelling.