Coming in many names, shapes and sizes and most common in the Tomato family, but does affect other nightshades and many other fruits even bananas, where you can get double, triple and more bananas sharing wht looks like 1 big skin, is a cluster of flowers, that has joined the centres around a single petal surround.
Most often the heirloom plant get this happening in the first cluster of flowers at the start of the season. This is the first time I have seen it happen to a F1 hybrid. The fruit is perfectly edible. Unfortunately the plant does put lots of resources to this complex tomato, and the chance of damage from bugs and desease is high do to its shape, and chance of cracking. It is best to remove it.
I let this one grow a bit to create a blog, as many time people think this is soil or poison contamination. So if you have not come across this before, there is no need to panic 😊. Let it grow or take it off, either way it is fine.
Iterestingly there is a tomato variety called voyager, or travelers tomato that has been bred to do this. The idea is you can pill pieces of and it stay together and not leak out its juces everywhere. It is an ugly fruit, and not a great tasting tomato.
For now, I will take thus one off my chefs choice F1 Bicolour.