<P> In 1983 , Mary discovers Azazel standing over baby Sam 's crib ; he had been feeding his blood to the infant . Upon being interrupted , the demon pins her to the ceiling , slashes her stomach and causes her to burst into flames . Her death inspires John to dedicate his life to hunting down Azazel , at the same time training Sam and Dean to hunt supernatural creatures . </P>
<P> In 1983 , Mary discovers Azazel standing over baby Sam 's crib ; he had been feeding his blood to the infant . Upon being interrupted , the demon pins her to the ceiling , slashes her stomach and causes her to burst into flames . Her death inspires John to dedicate his life to hunting down Azazel , at the same time training Sam and Dean to hunt supernatural creatures . </P>
supernatural what killed sam and dean 's mother
supernatural what killed sam and dean 's mother
the demon pins her to the ceiling , slashes her stomach and causes her to burst into flames
the demon pins her to the ceiling , slashes her stomach and causes her to burst into flames