The Bull
Throughout the novel, Grendel condemns animals for the unthinking manner in which they follow patterns. In his view, animals, like machines, pursue tedious routines determined by outside forces (an engineer or programmer in the case of machines, nature and instinct in the case of animals), never making imaginative leaps of their own. The bull that attacks Grendel in the tree is one of the most powerful examples of this unthinking action. The bull, which continues to attack Grendel in the same, ineffective way time and again, comes to represent the world, which similarly acts in a brute, uncalculated manner.
The Corpse
Just before he hears the Shaper describe how he is the descendant of Cain, Grendel stumbles upon the dead body of a Dane who has apparently been murdered by a fellow Scylding. Grendel takes this corpse to represent the essential, inarguable falsehood that lies at the center of the Shaper’s myth: the division between human and beast is not as clear-cut as the Shaper would make it seem. Man is just as capable of cruelty and violence as Grendel; it is a lie to say that one of them is cursed while the other is blessed. The dead body represents the burden of the curse that both man and Grendel must bear. However, though Grendel thinks as much about the corpse, he also feels overcome by the beauty of the Shaper’s elegant, unambiguous moral system. Grendel stumbles into Hart with the corpse in his hands, yelling “Mercy! Peace!” The corpse expands in significance, becoming not only a symbol of man and Grendel’s twinned fate, but also of Grendel’s desire to be accepted by the human community with which he has so many similarities. Later, the symbol of the corpse is echoed in the figure of the Danish guard whose head Grendel bites off, signaling the beginning of his twelve-year war with humankind.
Hart
For Hrothgar, his meadhall is a symbol of both his great political power and his altruism. For the Danish community at large, Hart is a symbol of the persistence of their belief: every time Grendel knocks down the door, the Danes tirelessly repair it. The fact that the Danes do so despite Grendel’s continued destruction mirrors their unshakable belief in their value systems despite the cruel, chaotic nature of the world at large.