What symbolizes obsession with death and decay in act 5 of the play?

In Act 5 of Hamlet, the skull that Hamlet holds while speaking to Ophelia in the churchyard symbolizes obsession with death and decay. The skull serves as a reminder of the transience of life and the inevitability of death. Hamlet reflects on the fact that even powerful and beautiful individuals, such as Alexander the Great and Julius Caesar, end up as mere dust. The skull symbolizes Hamlet's preoccupation with mortality and the meaninglessness of life, highlighting his deep existential angst and philosophical contemplation of the human condition.