An Umamusume fan used AI to replace every car in Need for Speed Underground 2 with horse girls.
Creator CyberNekoYuki started with a simple idea. “The plan was to swap in two or three characters. Then my friends joined me for some offline LAN races, and I somehow ended up changing the whole roster.”
He ended up with 36 characters racing around Bayview, including Oguri Cap and Haru Urara. The mod was never released publicly, just used for private sessions.
Going from a couple of swaps to the full roster is exactly how these things go.