Cornelius Evazan is, in StarWars.com's description, "a grubby, scarred smuggler from Alsakan" who "was once a promising surgeon, but became notorious for conducting cruel medical experiments". He and Ponda Baba pick on Luke Skywalker in the Mos Eisley cantina, with Evazan boasting of a death sentence in twelve systems, and pay little attention to the old man in dusty robes who came in with him.
The exchange is four lines long and has been quoted for nearly fifty years, largely because it is the moment the film establishes that this bar is dangerous and that Kenobi is more dangerous still. Both men reappear on Jedha in Rogue One (2016).
Catalogue entry. This figure has a verified record here rather than a full write-up — the encyclopedia labels its own depth instead of padding it.