I can't find any canonical reference on this site.
Do we know what Sirius Black's boggart form is?
I can't find any canonical reference on this site.
Do we know what Sirius Black's boggart form is?
We don't know Sirius' Boggart form. It's not explicitly stated in any of the novels, nor has it been revealed in any of JKRs posted interviews, nor via her twit feed, nor on Pottermore.
There's always the possibility that it's a Dementor or Azkaban Prison itself, but given the extreme risks Sirius Black takes to see his godson at the train station and to watch him playing Quidditch, I think we can be reasonably sure that his boggart would have been Harry's dead body. In earlier years, it was probably James Potter's dead body.
Harry turned his back on Dumbledore and stared determinedly out of the window. He could see the Quidditch stadium in the distance. Sirius had appeared there once, disguised as the shaggy black dog, so he could watch Harry play … he had probably come to see whether Harry was as good as James had been … Harry had never asked him …
Harry Potter and the Order of the Phoenix