Identification: Identity crisis

I received a clipping of this plant from my daughter's Grandmother. Is it a succulent or something else? It has send out and upwards two 14" "spikes" in the last week or so. I have in a south facing window (year round) which gets a lot of sun and heat and it appears to be doing very well there. Just hoping for an ID after searching the internet and having no luck.

 

Might be a "pencil cactus" (Euphorbia tirucalli)

 

Rhipsalis cereuscula

 

Thanks for your replies. I had initially thought it may be a Euphorbia of some type but it lacked the milky substance when nicked and it drooped rather than stood upright. I went searching again following TonyR's reply and that has to be it. New to the succulent and cacti plants. Am hoping I am better suited to plants that will survive infrequent watering.

 

This is a tree-dwelling jungle cactus, it won't want to get real dry.