[rogertb]

This rogue is growing amongst my runner beans, I quite like it, it’s about the size of a tennis ball at the moment, will it develop into something edible ?

[mumofstig]

It's obviously from the squash/pumpkin/courgette/cucumber (Cucurbitaceae)family - but what it actually is, is very hard to tell.
It may, or maynot, taste nice depending what the parent plants were.

Sorry that's not much help