A stage mix. This stage combines Fourside, from Melee, with Saffron City, from N64. The main stage is Saffron City, but the background and UFO are taken from Fourside. Here's a picture of the stage:
Note that I've made this using a texture hack for Smash Bros 64 they made in emudesc. The original stage looks like this:
So credits to everybody who worked on the original retexture for N64 emulators.