In Suzanne Collins's books and the film adaptations, Thrash is a tribute from District 1 who is killed by Katniss Everdeen in the first Hunger Games. Katniss shoots Thrash with an arrow while he is attacking Rue, a young tribute from District 11, whom Katniss had formed an alliance with.
Perhaps you're thinking of another character or story? Can you give me more information about what you're asking?