Ok have a question been bothered about my son keeps watching Halloween prop videos on his pad and we…

Ok have a question been bothered about my son keeps watching Halloween prop videos on his pad and we have had this on going fight of making him change the video n he gets mad reason I change it is because I don’t want him getting scared or having nightmares but he keeps going back to them I have cleared them off his history again and again n he happens to find them again so should I just let him watch them?