In Joss Whedon's TV series Buffy the Vampire Slayer, Buffy stand for life and the moment. Her 'watcher' (the Englishman Rupert Giles who trains her and is a general mentor figure) tells Buffy's mother (Joyce Summers) that Buffy is not good at history because she lives in the now and history is very much in the then.
When she is practicing for the SATS exam (general school examination of aptitude in the US, providing an opportunity for those who don't get grades to show what they have got), one of the answers Giles reads out to her refers to the second law of thermodynamics. This law refers to energy moving from hot gases to cold, and its more generalised conclusions include the claim that energy keeps reducing in a system. This is why there could never be a perpetual motion machine. In general the universe is losing energy and keeps cooling down. that loss of energy is also a collapse of the system into chaos. Chaos is what Buffy, Giles and all the good characters are fighting. Demons are strongly associated with chaos. Giles tells his former friend Ethan Rayne, that they stopped being friends when Ethan started woshipping chaos.
At the end of Season Three when her vampire lover with a soul, Angel, is dying she tells the pompous watcher Wes, that she does not know what he is talking about when he refers to the ancient laws that stop the Council of watchers from helping to cure Angel. She just knows her lover is dying. History and laws are foreign to her, she lives according to the passions of the present.
Buffy comes back to life from death twice, at the end of season one and at the beginning of season six.
As life, as the person who lives in the moment, Buffy is also a chaotic force. The struggle with chaos, what Freud called the death principle, what physicists call entropy, is what Buffy fights and is what she longs for. As the vampire Spike explains to her in season 5, she is drawn to death and experiencing the moment of death. A slayer guide explains to her that 'Your gift is death'. Buffy longs to entropy at that time, she with draws from her friend into herself , and dies a euphoric death to save the world from demon dimensions.
Buffy is chaotic in a positive sense, she resists and questions authority. This means introducing entropy into hierarchical ordered system. As the bad colonel points out to her boyfriend Riley, his resistance make him an anarchist.