Same question from another member recently -- I want to add that sometimes this happens because the commercial growers spray them with bloom boosters (sometimes hormones) to make them more attractive in the store ....
Subject: Wisconsindead's 2017 Garden
applestar wrote:It's a megabloom. If all of the fused blossoms are pollinated evenly, you will get a megafruit (you may want to assist). Some varieties are prone to this, and especially strains of varieties selected for competition sized fruits.
Also, when the fused blossoms are obviously a twin, with the long paste types like Roma, you can end up with fused twin fruit that are interesting-looking. Actually most fused fruits are interesting and 3 or fewer make decent fruits without the severe uneven pollination and pithy core issues.
Definitely please add photos and follow up with their development and progress
