Bowser's Theme (Beta Mix) is a high quality rip from the game Super Mario 64.
This rip features Meet the Flintstones with the Super Mario 64 soundfont instead of Bowser's Theme.
It is a reference to the original rip Bowser's Theme - Super Mario 64. The original was posted before the reboot (Meet the Flintstones is associated with 7 GRAND DAD, which is considered the main meme) and featured the Simpsons Theme. This rip, however, is posted during the reboot itself, when the Simpsons rips are frequent and there are no 7 GRAND DAD or Flintstones rips.
SiIvaGunner also changed the description to "Please read the channel description" and posted the comment "I only upload high quality rips" for this rip despite the channel still being in its rebooted state.