The phrase itself comes from online gaming and internet slang rather than a single show or film. Ez is shorthand for easy in match chat, no cap means no lie, and lmao adds the laugh, so the combination reads as a boast that is meant to be funny rather than serious. It spread through streams, voice chats and short gaming clips, where a five-second taunt fits neatly at the end of a round. Its staying power comes from that mix of confidence and humor, which works for wins in almost any competitive game.