There’s got to be something with her and companions. At this point she’s got the Pond-River-style name (thank god at this point she doesn’t seem to be part of another tedious River Song storyline), she wore Clara’s Face The Raven outfit and called the Doctor a “clever boy,” and she ended the episode in Romana’s fur coat. I’m fully down with her trolling the Doctor/us like this - I just hope she’s not the Master again. There is no character in Doctor Who I’m as sick of as the Master.
(My outside bet is maybe the Meddling Monk? But that’s probably wrong.)
I rank Space Babies pretty highly too, because while I really enjoyed the episode, my daughters LOVED it. They've been obsessed with Doctor Who after seeing it –– my five-year-old made me call her Captain Poppy for a full week.