It's not intentional. When you get the blood tree to a certain level, the sprite sheet is swapped out with an alternate version where everything is supposed to be more disheveled and hollow, to show how your chaos is corrupting the world with how strong it's getting . But I overlooked the fact that some sprites don't exist at all in the "corrupted" sheet. That's something I ran out of time on and the only effect you can really see is your skeletons become bloody and take on a twisted facial expression when your chaos/tree level reaches that point.