Mario's birth and body — "People who’re somehow burned at birth…"
People who’re somehow burned at birth, withered or ablated way past anything like what might be fair, they either curl up in their fire, or else they rise. Withered saurian homodontic Mario floats, for Hal.
Context
Hal's secret credo about his brother, and the theme's thesis sentence: deformity as fire you either curl up in or rise from. "Withered saurian homodontic" compresses the whole physical dossier into three adjectives (n.119 glosses homodont: every tooth a bicuspid) and then gives it a verb from another physics entirely — Mario floats.