This is a Chayote fruit. We came across it at our local salvage store. My girls and I had never seen anything like this before so we bought one to try.
This is GirlyGirl9 giving him bunny ears. We think he looks like a grumpy old man so we named him Mr. Grumpy Fruit.
Wikipedia says that it's an edible plant that belongs to the gourd family.
We cut it up last night to give it a try. We thought it felt like an apple and at first thought it tasted like, well...nothing. After taking a bigger bite GirlyGirl9 said it tasted like grass. So I took another bite and totally agree with her. It tastes just like the air smells when the grass is freshly cut.
We probably won't be buying a Chayote again anytime soon, but it was fun to try something so different.