Half a tomato is rotting on the vine...

I've been watching this pink oxheart tomato ripen on the vine. It appeared fine yesterday, but today, I noticed it was half rotten. I haven't cut into it yet. Any idea why a tomato would do this? Is an alien going to pop out of it?

We tried Heirlooms for the first time this year. They must be picked when barely showing color or else they crack & go to pot.

Heirlooms are pretty much all we plant. Mine don't crack etc. They are delicious! They are just now starting to produce well.
I'm thinking there's a worm inside of that half of the tomato.

Thanks birder17. I'm afraid to cut it open, and there's no holes in the tomato. That's the first thing I looked for.

CountryGardens, if your tomatoes are cracking, it might be due to uneven watering. I've been growing heirlooms for years and they only crack when we have heavy rains after dry periods.

Here it is cut open. In my years of growing tomatoes I have never seen anything like this. As you can see from my first post, it isn't even bruised, the skin is fully intact.

I have heard of Blossom End Rot (rarely) occurring in the interior of tomatoes, although it looks like maybe some kind of worm could have entered near the stem.

Do any of your other tomatoes have this symptom?

Yes, it still looks like worm damage to me.
Otherwise, I will just blame it on a tomato virus. There's a gob of them.

tobasco: so far, no other tomatoes show this symptom, but this is early days.