Question: Which symbiotic characters were introduced in the two-part episode of Spider-Man? 
Sentence (from "The Time of Angels"): Moffat utilised the two-part episode to bring back a couple of his previous creations: the Weeping Angels from his series three episode "Blink", and River Song (Alex Kingston) from the series four episodes "Silence in the Library" and "Forest of the Dead".
Relevant evidence: No