Floating End Crystal fire break the obsidian then break the ender crystal or you can break the crystal then the obsidian which is easier!

The floating fire is also unbreakable! once you have made it float

Unless you put water it is unbreakable by hand

Also you can blow up the ender crystal then break the obsidian

Also another bug with it is that the fire doesn't burn you in survivial

may have to be tried a few times