Here is a weird one guys. So I hit an aiptasia anemone with some kalk and water and some of it fell on this dendron.
It clearly did not like that and retracted. The next morning I woke up to this:
Some how it split in two and attached itself to cave behind the original. How did it do that? Anyone have an idea? If you look in the cave you can see it is upside down, deep in the cave.