This was drawn for an artist known as azlan or kaaservant. 'Azlan' is actually the name of one of his characters.
This artist became extremely popular for his high-quality drawings featuring kaa the snake, hypnotizing and making-out with various anime characters. But he became fed-up with people constantly pestering him to draw more kaa pictures, so he decided to make a request of his own: if he recieved enough fan-art of his original characters, he would draw more pictures featuring kaa the snake. This was one of the pictures I made for him. In the end, there weren't enough pictures, so he took his work elsewhere. (Hentai foundry)
It just goes to show that an artist might specialize at something, but they'll get tired of doing it if that's all people ever ask for.
There's an audience for just about everything. If an artist mostly draws what they enjoy, they attract a like-minded audience. But if they mostly draw what other people want, they'll just end up attracting a demanding audience.