In honor of the 10th anniversary I think it's time to say this
(spoilers for dolce - 03x06)
Kuru is an illness that is as rare as it is deadly, a neurodegenerative disorder that has often been compared to mad cow disease. It is a form of transmissible spongiform encephalopathy caused by the transmission of abnormally folded proteins and it causes a range of symptoms like dody tremors, gradual loss of coordination, emotional instability, which takes about a year from the onset of the first signs to kill a person.
This disease was transmitted in Fore funerary rituals which consisted of eating the dead's brain, leading to a widespread epidemic in the community.
Now please consider that Dr. Hannibal Fucking Lecter studied medicine, and then psychiatry.
You cannot tell me he didn't know about kuru.
So please do consider the implications of his gesture.
Hannibal wanted to eat Wills brain. In his mind he knew how in another life, that would have gone. Eating the ones you love and letting them slowly murder you, not with grief but with something you can physically never heal from. He would literally let Will kill him by eating his brain. He would get rid of Will but eventually death would claim him, and bring him back to Will.