Lagtrain is a viral Vocaloid song produced by Inabakumori, featuring the character Osage-chan in a distinctive monochromatic animation style. Released in 2020, the music video depicts the character rocking rhythmically while waiting at a train station, which quickly became a sensation on platforms like TikTok and YouTube. The meme is often used to represent feelings of stagnation, social awkwardness, or literally 'lagging' in real-life situations. Its unique art style has inspired countless fan parodies where different characters are inserted into the looping train station animation, maintaining the iconic black-and-white aesthetic and rhythmic movement.