Why did Dio cut off his head and not regenerate his body? In the first season of Jojo's Bizarre Adventure, when Dio falls off a cliff, he cuts off his own head. 


Why?


At the end of the season, we see him in Jojo's wedding boat, his head in a container. 


Why didn't he regenerate a body during all this time?
Hamon was spreading throughout his body, and if he did not separate himself from his body, Dio Brando would die.

The Hamon that destroyed his body, probably prevented him from regenerating his body. Dio Brando in the final episode of Part 1 says something along the lines of &quot;This is the man who brought me to my current state. Give him [Jonathan Joestar] a swift death.&quot; This alludes me to believe that it was because of JoJo's Hamon that Dio Brando is unable to regenerate his own body, and thus wants to take over JoJo's.