Mushroom Kingdom II - Super Smash Bros. Melee is a high quality rip of "Mushroom Kingdom II" from the game Super Smash Bros. Melee.
The rip is actually filled with sound effects from the same game in reference to "Super Mario 128", an event from the game happening on the Mushroom Kingdom II stage where the player has to defeat 128 tiny Marios. This event is infamous for its loud and repetitive nature.
During the entirety of the rip, high-pitched Mario voice clips, huge hit sounds, and a cheering crowd are heard. At 0:21, the sound of Poké Ball being thrown is heard, but the Pokémon is Vinesauce Joel saying "GRAND DAD!". At 0:50 is heard the fanfare of a Party Ball opening, followed by the melody of the Hammer item replacing "Mushroom Kingdom II"; when the Hammer stops at 1:00, "Mushroom Kingdom II" starts again from the beginning. At 1:09, "Mushroom Kingdom II" and the fighting noises stop and the announcer from the game declares "A new record!"