The 'It's a Gundam!' meme originates from the classic 1979 anime series Mobile Suit Gundam, specifically from the panicked reactions of Zeon soldiers upon encountering the overwhelming power of the RX-78-2 Gundam. The line, delivered with high-pitched terror, became an enduring trope within the mecha genre and the global anime community. In internet culture, it is used to express sudden realization, shock, or the arrival of something legendary and intimidating. It has evolved from a niche anime reference into a versatile reaction image used to highlight any person or object that suddenly dominates a situation with its sheer presence or reputation.