Joseph Ellis-Stephenson (born 19 October 1988), better known by his stage name Dot Rotten or Zeph Ellis, is a British grime MC, rapper, singer, songwriter and record producer from Lambeth, South London.

Having released a series of mixtapes independently in the grime scene under the names Young Dot and later Dot Rotten, Ellis signed to Mercury Records, releasing his debut studio album Voices in My Head in 2013. After leaving the major label, he has since released several independent EP's and projects, as well as later changing his name to Zeph Ellis and focusing on producing.

He is known for introducing various sampling techniques to grime production, and creating the style of singing hooks on grime tracks. These styles can be heard throughout his discography from the early Young Dot era to his present projects under the Zeph Ellis moniker.