Toby Fox is an American video game developer and music composer. He is best known for developing the game Undertale and the demo for his project Deltarune. He has also composed music for the webcomic Homestuck, as well as for the video games Hiveswap, Escaped Chasm, Little Town Hero, Pokémon Sword and Shield, and Super Smash Bros.. He is also known online as FwugRadiation or as Toby "Radiation" Fox.