I've always liked mermaid images. I doodled this one in my journal over the weekend. It's not the greatest, but I only had limited supplies since I was on a trip. I drew her with a graphite pencil and then colored in with watercolor crayons. I brushed over parts with a wet brush, which works great over watercolor crayons or pencils.
You can see some other mermaids I've made here, here and here. As you can see, I like mermaids, whether painted or drawn, flat or 3D, rendered in jewelry, ATCs, collage, shadowboxes or really any medium. I even have mermaid costumes for my Blythe dolls. But I would call this just a fondness or attraction, not an obsession. An obsession with mermaids would probably involve an adult size costume, and I can safely say I do not have one. What is your "almost-obsession"?