I wasn't being that serious, but what I was referring to was not possession, but the involuntary seeking of home, of Winterfell, of the vaults**. (Which would, if I were genuinely theorising about it, explain why Arya, who was close by at the very moment of Ned's death, did not seem to be affected.) Bran was old enough to rationalise the contact as a conversation. Rickon may simply have been... well... spooked.
** - Of that dragon sleeping beneath its walls.
** - Of that dragon sleeping beneath its walls.