15.ai, also known as Fifteen.ai, is a web-based artificial intelligence tool that generates realistic text-to-speech voices from popular media characters. Launched by developer 15hc, the platform gained massive popularity on platforms like YouTube, TikTok, and Twitter, where creators used it to make characters from 'Portal,' 'My Little Pony,' and 'SpongeBob' say unexpected or humorous things. The meme often revolves around the contrast between a character's innocent original context and the absurd or controversial dialogue generated by the AI. It has become a fundamental tool for high-quality audio shitposting and video parody creation across the web, frequently referenced through its distinctive user interface.