The "Mystery" seed has revealed itself....sorta

[hoodat]

It may have crossed with a bush acorn squah if you had any of them nearby.
I bought some supposed to be Bush Acorn seeds this year and they're running all over the place.

 

[ducks4you]

The last time I had any melons was about 5 years ago. I watched with great anticipation as one beautiful cantaloupe developed and get bigger and was about ready to harvest. Then my big horse (16'2hh TW) reached over the fence and helped himself!! Oh, well...better him than the bugs!!

 

[boggybranch]

It, definitely, appeared to be something like a canteloupe...in look and smell. Unfortunately I lost them to Fusarium Wilt.....the whole lot. Gonna give it another go next year....in a different spot, for sure.