Nightmare Child

The Nightmare Child is an obscure object, location, area, or living creature, of which very little is known. According to the Doctor, Davros' ship flew into its "jaws" during the first year of the Time War, supposedly destroying him and his ship in the process. This event happened at the Gate of Elysium.

Suggestion: Nightmare Child seems like the name of a ship (ref: Thunder Child from War of the World) or it could be a black hole or other spatial anomaly

Dalek Caan, who escaped from 1930 using an emergency temporal shift (DW: Evolution of the Daleks), arrived in the Time War (despite it being Time-locked) and flew into the jaws of the Nightmare Child to save Davros from destruction. (DW: The Stolen Earth)