The concept imagines a Mario game with gameplay similar to Crash Bandicoot.
Game Developer known as Funkyzeit Games has demonstrated Super Mario RTX, an absolutely mind-blowing game concept inspired by Nintendo's Mario series and made using Unreal Engine 5. The video shared by the author depicts high-detailed Mario jumping on question blocks and obliterating Goombas with fireballs in an eerie and dimly-lit game environment that looks similar to those from Crash Bandicoot.
According to Funkyzeit Games, this concept depicts a Mario game the developer always wanted to play. Please note that this is just a fan-made gameplay video and not something that will ever be published as a full-fledged game or monetized.