Leaves look like a cucumber, flowers look like a cucumber and the fruit looks like a very round cucumber.
If the fruit has these small, almost spiky clear globule bumps on it, that's another cucumber trait. I'd open it up, and smell it. If it smells like a cucumber, it's probably some form of cucumber.
As to what variety it is to cause it to look like that, it might be a lemon cucumber or a green apple cucumber. Or simply a cucumber that makes really round cucumbers. I'm not really sure.