I'm TOTALLY with you da bill, I reckon R.A.B. is Regulus Black too. I went looking to see if his middle name was mentioned on the family tree but alas, no.

K. So you're all gonna think I'm really dumb but I'm wondering if it was really Dumby who died.
I think his insistence that Harry gets Slughorn's memory was a little full-on/ very unDumbdledorey.
I also reckon that the real Dumby would not have taken Harry on a dangerous mission with him.
Additionally, what was with the begging before he was killed???? That's not MY Dumbledore!!

What you think about the idea that they'd kidnapped Dumbledore and it was really Pettigrew taking Polijuice Potion?? Thus the bung hand and the begging and the ease with which Snape killed him. ????????