[Plant-biology] What is it?

[mag]

	I planted 3 Rouge pumpkins, 3 New England pie pumpkins, 3 "Sweet Mama 
Buttercup" squash, an acorn squash, a butternut squash, and 3 yellow 
hybrid zucchinis in a manure pile in my garden. The vines have gone 
crazy and it's hard to tell what's what. I ended up harvesting a small 
yellow squash/pumpkin and have no idea what it is! It is 5-6" across, 
yellow (waxy looking) with small green lines, and has a cup-like  end 
where the blossom was. Is this just and immmature pumpkin? Previous 
pumpkins I've grown were green then orange. Picked it four days ago and 
it has maintained its yellow color? Could it be a cross? Does this small 
fruit sound redognizable to anyone? Thanks.              mag