What in the world happened with my cauliflower?

I woke up one morning expecting some of my cauliflower to be ready to be harvested. I was alarmed when I woke up and saw this:

A giant cauliflower has eaten up the spaces around it. What happened? I can't seem to harvest it by normal means or by using a scythe. The Wiki doesn't say anything about this phenomenon on the cauliflower page. I planted it on soil that was tilled with basic fertilizer if that helps.

Solution 1:

You got what is called a giant crop. You have a slim chance of getting one with cauliflowers, melons and pumpkins if they are planted in a 3x3 grid. Giant crops don't appear giant until they've fully matured, and it is possible to not harvest mature crops right away and have them fuse the next day.

Giant crops yield twice as much produce as their regular-sized counterparts, but they must be harvested using an axe.

There is a small Giant Crops section on the wiki on the generic Crops page.