Magnum, PI

Can anyone enlighten me as to why I imagined a thrash metal version of the theme to old heavily moustached cult show Magnum PI? Its not like I’ve seen it anywhere recently, I don’t know where it came from, but for some reason when one of my colleagues shoved on some very loud rock after closing time while they were tidying the store I suddenly imagined the growling singer and thrash rock they had on covering the theme from Magnum PI.