[Things Joker could do: give the Doctor a straight answer.]

[Things Joker will do: not that]

[Instead, he bites back the desire to breathe in sharply or laugh, and just clears his throat.]

Well, they’re sneaky little buggers, wisps. Turn yer back, and poof! Left with nothin’ but the hairs on yer neck and a funny feelin’ in the back of yer mind. Hair-raisin’, it really is.