It definitely looks like a cereus. Could be one of the night blooming varieties. This big guy is mine. Totally overgrown and in need of major division. They have a tendency to thrive on neglect in the tropics. Since you are in Orlando, you will have to protect it if you get frost. You can divide at the joints like Baja recommended. Best in a large container with a wooden post for climbing. It will get Big. Check out YouTube. There's some great videos on growing hylocereus or dragonfruit on there. Lots of ideas on how to pot it up and maintain its funky growth.
