his name is Dennis Mitchell
Dennis is the scion of the Mitchell family.
Dennis's last name is "Mitchell".
Dennis in Hawaiian is Denekē.
You use Dennis's when meaning, "belonging to Dennis." It's the possessive form of Dennis, which is a name.
Dennis Rodman was born on May 13, 1961
Jay North played the child, "Dennis", in Dennis the Menace.
Dennis Adams has written: 'Dennis adams'
Dennis Alink goes by Dennis Daja.
Dennis Kucinich goes by Dennis the Menace.
Dennis Looney goes by Dennis Fitzgerald.
Dennis Overweg goes by Dikke Dennis.