Helix Intelligence

Helix Intelligences were sentient astral/energy forces that resided in spirals of pure energy. The best known of the intelligences was the Mandragora Helix, (TV: The Masque of Mandragora) which resided in unchartered regions of the Time Vortex. (PROSE: Doctor Who and the Masque of Mandragora)

They possessed archetypal memories, able to absorb emotions, consciousness, and genetic cells of others. (PROSE: Exodus Code) They had great manipulative power that could recreate stone structures or destroy beings, making their skin appear blue and crystallised. Their energies could be spread out, but this would exhaust their being.

The Tenth Doctor explained that Mandragora originated during the Dark Times, commenting that it should never have been released from its dimension, (PROSE: Beautiful Chaos) implying the helixes originated from outside the universe, since Mandragora was "old even when this universe was born." (COMIC: The Mark of Mandragora) The helixes existed everywhere in the galaxies before any life forms, and may have been responsible for the first life forms.

Tn the 1960s a cadre of physicists, which some said were a cult that experimented with LSD too much, posited a theory that a "powerful sentient astral force" was caught in the Big Bang, part of the force breaking off and fusing with the centre of Earth while the solar system was forming. They believed the energy force gave Earth its organic nature and that evolved from the force and was protected by it.

Helixes were neutral, impassive energy forces, (PROSE: Exodus Code) having no need for human beings, although they could possess them. (TV: The Masque of Mandragora) The Greeks called the helixes Titans, the gods of the gods. (PROSE: Exodus Code)

Apart from the helix trapped within the Earth, Mandragora manifested on Earth in the 15th century, (TV: The Masque of Mandragora) 1863, (PROSE: The Eleventh Tiger) the 1990s, (COMIC: The Mark of Mandragora) and 2009. (PROSE: Beautiful Chaos)

Helixes were bound by the alignment of stars, only having access to the universe at certain times, (TV: The Masque of Mandragora) similarly to the Great Old Ones who also existed before the Big Bang. (PROSE: White Darkness)

Behind the Scenes
The Mandragora Helix is presented in Masque as a "non-physical" object/location containing a living intelligence, which is one of several helix intelligences. The novelisation makes reference to multiple intelligences within the Mandragora Helix.

Although we only have its behavior to go on, it was never explained if Mandragora was its own race or a hive mind, since no other helix was referenced until Exodus Code. It is inferred, then, that Mandragora is an intelligent location.