Dalek Symbiont

The Dalek Symbiont was a Dalek mutant infused with DNA extracted from a Great Vampire. It was created in the Dark Times by the Dalek Prime Strategist and the Dalek Scientist of the Dalek Time Squad.

History
Believing they had failed to correct history after the Battle of Mordeela, the Dalek Time Squad began a backup plan of extracting and weaponising lifeforms unique to the Dark Times. Whilst the Dalek Time Commander and Dalek Executioner abandoned this plan in favour of the Dalek Emperor's plan for the Ultimate End, (PROSE: Mission to the Known) the Prime Strategist and Scientist persisted, now intent on creating a more biologically efficient form of Dalek known as the Symbiont.

They decided to focus on capturing a Vampire, sending a scout ship to Entranxis to capture Ikalla, who had escaped an earlier Dalek attack on the Free Undead. The scouts failed due to the interference of the Eighth, Ninth and Tenth Doctors, however the Daleks encountered a coffin ship transporting a Great One shortly afterwards. They raided the vessel and captured the Great One, keeping it in a scout ship launch bay aboard the Dalek Time Squad's saucer. Observed by the Tenth Doctor and Gelsin, who had infiltrated the saucer, the Scientist extracted DNA from the Great Vampire and infused a Dalek mutant with it, causing a massive power drain to the saucer. The resulting creature was a considerably larger than normal mutants and was unkillable due to being undead.

The Strategist presented the finished creature to the Commander to defend himself for causing a power drain. In preparation for the attack on pre-Time Lord Gallifrey in the realisation of the Ultimate End, the Strategist ordered for numerous Silver Dalek drones to be given the Symbiont's DNA, making them undying as well. The original Symbiont creature was dispatched to Birinji to kill the last of the Kotturuh, Inyit.

The hybrid drones proved highly effective in battle, with the three Doctors unable to stop their advance and being forced to consider sacrificing themselves to create a paradox to wipe out the Daleks. However, as the original Symbiont approached Inyit, she used the last of her energies to judge it and award it a lifespan of mere moments. It and all the hybrids sharing its DNA quickly perished when their new lifespan caught up with them. The Daleks' assault was thrown into chaos by their deaths, as the Time Squad feared the judgement may spread to pure Dalek DNA, enabling the Eighth Doctor to defeat them by using an explosive to force their saucer into the Time Vortex. (PROSE: All Flesh is Grass)