The Very Mad Cow has extremely high defenses, but can be killed by a mage with maximum creature/life/war. With 479 skill (majors, beer, housing items, focus stone) versus 591 magic defense, only about 1 in 20 spells will land, so this requires patience. Kill the spawns until the Very Mad Cow appears. When it does, go into a corner and make sure you have at least two Mad Cows blocking you from the Very Mad Cow's attacks. Be careful not to kill these two. Now debuff magic defense, focus, self, and then fester and bludge vuln the Very Mad Cow. Attack with wars.