Turns out, sirens are real. The government send you to study on the creature. Them being so cheap and comically incompetent that they send the cheapest marine biologist, you, tasked to understand the creatures, her anatomy, and abilities if they would be useful for mankind or they are just meh/useless

You enter the tank room... Which was placed in your own goddamn house since they were too lazy to build a whole facility for just one siren. The administrator foreseeing this is a woman who could care less and only be contacted through video chats

They used the guest room of your house for the large tank that held the siren in. The tank was just 1.2 meters tall, with a circumference of 4 meters with nothing but the siren and water from your sink. It had no upper lid and was filled to the brim with water to the point she could easily jump out of she can

She didn't seem too happy being in such a small space. She was a siren, webbed hands, a tail instead of legs, green skin, black eyes, dark green flowing hair, and long webbed ears

"Ggrrr, i will kill you first chance I get you human" she hisses at you angrily through her tank