Ulysses: Hey, Siren. What’s with that squeaky scream?
Siren: There are three mosquitoes flying towards me. They are terrifying.
Ulysses: I see. Hey, speaking of the mosquitoes, have you heard of this ultrasonic pest repelling devices that you can get from some retailers? Allegedly, the electronic device emits high frequency sound that is only heard by mosquitoes, but not human beings. The manufacturers say that you can carry them around and the mosquitoes will not come near you because they hate the sound…
Siren: Good idea. Maybe I can reproduce that with my ultrasonic shriek. AH-AHHH…!
Ulysses: (Shouting) Can you stop that?!! (Siren becomes quiet.) Much better now. The scientists have proven that it has no effect whatsoever on any insects. So you might as well save the trouble.
Siren: So why do you bring it up?
Ulysses: Well, some scientist seemed to be inspired by that and invented a “teenager repellent” with the same concept.
Siren: You mean teenagers that bite like mosquitoes? Wow, that makes them vampires - if they suck blood like mosquitoes do. So the repellent you are talking about must be Van Helsing, or Buffy the Vampire Slayer, or…
Ulysses: Well, I am not talking about vampires, and certainly have no idea why Van Helsing and that Buffy girl are doing in our conversation. I mean that scientists locate a specific frequency which most young people under 25 can hear while most people over 25 cannot.
Siren: Like imaginary friends?
Ulysses: Er. Not exactly. It’s more scientific than childhood fantasy. Anyways, they devise a transmitter that releases unpleasant high-pitched noise that only annoys teenagers, so that they will clear out of the vicinity where the device is set up.
Siren: But why can’t adults hear the sound?
Ulysses: You know people say that your life starts downhill once you pass 25. One’s hearing ability deteriorates in his or her early twenties as well. In a word, old people are not as sensitive to sound as young people are.
Siren: I think that device is a form of discrimination.
Ulysses: Yeah. Many people have been arguing against treating our teens as pest infestations, thinking it a violation of their human rights. However, some surly young people are prone to vandalize public property when they congregate together. The people using this device only turn it on when there are boisterous groups of young……
Siren: No. I mean it is discrimination against the old! It is even an invasion of privacy! You see, judging from my reaction, they can know whether I am older than 25 when they turn on the device.
Ulysses: It should not bother you anyways. You told me that you stay eighteen forever, right? I assume you don’t age like us mortals?
Siren: Of course not, I am a siren, the enchanting sea goddess. I stay young.
Ulysses: Ha. Liar. You must be much older than 25.
Siren: . . . Why do you say that . . .?
Ulysses: Well, I have the device on the whole time we are having this conversation, and you seem pretty unperturbed to me. The noise is even somewhat tingly for me, and I am in my mid-forties. Judging from your composure, I would say you are at least 150 years old…
Siren: Ah!!!! Please someone bring me a Ulysses repellent!!! (And a mosquito repellent, if you may!)