Regeneration hacks, sounds like it to me. How regen (as it's commonly known) works is it speeds up the ticks inbetween natural regeneration, which in turn affects the ticks of consumption and/or any other naturally periodic effect on the player, which is why you heard a loud noise (most likely from consuming food or sprinting rapidly). Unfortunately as it is, regeneration hacking was thought impossible, yet hackers have used various methods of exploiting vulnerabilities within the game itself to make this possible. Lots of regen hackers on MCSG at the moment, very annoying and a major inconvenience indeed. All we as a community can do is, well, exactly this- report.