Invasion of the Pod People?

Found this strange growth in the garden. It's gigantic. It looks like it's about to split open and some slimy creepy THING come slithering out. What is it?

It's a Casaba melon, and this is my best year yet growing Casabas. This one is a typical specimen. It weighs about 20 pounds. Casabas are huge football-shaped melons from Turkey, first grown in California (and maybe the United States) right here in Chico by John Bidwell. I got the seeds last year from Seedsavers Exchange, and this year planted seeds that I saved from last year.

They are absolutely delicious. Out-of-this-world wonderful. The flesh is pretty much the same as a cantaloupe, but better than any cantaloupe I've ever had---creamy, sweet, yummy, and highly aromatic.

For some reason, there is another melon that goes by the name casaba, which is more like a honeydew, and not as sweet as a Bidwell Casaba.  As far as I know, this is the real deal, just like General Bidwell used to grow.