Mega bloom. Happen sometime on hierloom varieties like CP. I remove it b4 it produces fruit

Or you can let it develop and see what kind of crazy fruit you get. You have to see it at least once...

I have the same problem. I saved seed from an heirloom tomato (don't know the variety), planted the seed, and then planted four of the plants into the garden. ALL four plants have that same flower bud at the top of very healthy looking plants! There are also some smaller buds just below these buds. What do you advise? If I cut them off should it revert to making 'normal' buds?
Thanks.

It will make normal blossoms without you having to do anything...the fused "mega blooms" are more of an aberration, though some varieties are more prone to produce them. It doesn't mean your plant is sick, just some environmental or genetic hiccup at the time the bud formed. I like seeing them from time to time.

The fruit that develops is just as edible and tasty as other fruits, just looks gnarly. So, cut it off if you don't want the fruit, or keep it if you do. The plant won't care either way! :) It's not really an issue unless you need "pretty" fruits for market or something.

So your other flowers on that plant isn't like that? Last year when I grew Black Krims, they all had big flowers like those.