The exact original recording behind Lucien thanks mister is not clearly documented, and it circulates mainly as a short user-uploaded clip. Its appeal comes from its simplicity: a sincere, childlike thank-you that works in any language context. Online it is used as a reaction sound for gratitude moments in edits, streams and short-form videos, where a formal thank you would feel stiff. Because the phrase is short, clean and universally understood, it has stayed useful as a wholesome insert for creators who want a quick, friendly payoff.