"Huntin' and Killin'" is a song featured in the Season Two episode, "The Mexican Staring Frog of Southern Sri Lanka".
This is likely to be the theme song of Huntin' and Killin', a hunting show on South Park public access television hosted by hunting enthusiasts Jimbo Kern and his Vietnam War buddy Ned Gerblansky. At the end of the episode that introduces the Mexican Staring Frog, Jimbo sings this song.
We're so glad you spent your time with us
While we slaughter our way through nature's guts
Come again and stay a while
We'll kill a lot more living creatures and make them bleed