As Jahmal Lightfoot tells it, Rikers Island correction officers pummeled him without any words — or any mercy — as he curled up into a fetal position inside a cell to shield himself from their repeated blows.

“Basically it was open season for them to do what they wanted,” Mr. Lightfoot testified on Monday in State Supreme Court in the Bronx.

Mr. Lightfoot, 31, returned to the witness stand for the second day and continued a harrowing, first-person account of the savage beating that he received in July 2012, when, Bronx prosecutors contend, the officers decided to teach him a lesson. He recalled that when he tried to cover his face with his hands, he was kicked in the groin and then officers pinned down his arms and legs.

Nine current and former correction officers are on trial in the beating of Mr. Lightfoot and an attempted cover-up. The most serious charge is attempted gang assault in the first degree, which carries a sentence of up to 15 years in prison. Other charges include attempted assault, tampering with physical evidence, falsifying business records and official misconduct.