Dark Matrix
From Tardis Wiki, the free Doctor Who reference
The legendary Dark Matrix was a repository of all the dead Time Lord's most evil, twisted and perverted thoughts. It was the antithesis of The Matrix. The Doctor confronted the Dark Matrix when the Valeyard- attempting to use its power to give himself a new body- had trapped it inside his TARDIS, provoking the Dark Matrix into destroying the TARDIS and itself when the Doctor convinced it that it was still a prisoner. (PDA: Matrix)
