Is This a Watermelon Gourd?

Hi there Lazyweb,

Anyone know what this is?  It is growing like crazy in our garden - and up our fence.  Unfortunately, I don't know what it is.  How is that, you ask?  Well....this thing sprung up from our compost.

All of my research on the web says that it isn't a pure watermelon - they sprout in much rounder shapes.  We have a few different types of gords growing (jack be littles and such), but they're all identifiable.  I remember what we had last year at Halloween time and remember throwing them all in the compost bin.  But....we didn't have anything like this.

Could we have created a super-beast?  A hybrid gourd out of our own compost?  I know that there are watermelon-colored gourds (see here) and that there are gourds that have half orange - half green.  This one is all green.  And...shaped like an eggplant!

The vine has about 8 of them growing, so perhaps I'll cut one open and see if the fruit is red?