Scarred Rex the Tyrannosaurus Rex is a major character of May 1987 draft of the 1988 film's script, The Land Before Time.
His true name is never revealed; the name given by the characters, 'Sharptooth', refers to the name of his species, and in production art, he is simply labelled "Tyrannosaurus Rex". Sharptooth was also referred to as "the Scarred Rex" in the 1987 draft of the film's script, and is referred to as "Rex" by Littlefoot in the same draft. Sharptooth has sometimes been referenced in media.
Sharptooth is also mentioned briefly in The Land Before Time X: The Great Longneck Migration, when Bron mentions to Littlefoot that he met someone who told him what happened to Littlefoot's mother.