( ) This creature is a parasite that does a lunge attack to latch on to you, the stages happen when another one infects you. You can remove them by taking dmg (or like scratching against a wall), if you remove them, you'll get an achievement called "You got a friend in me" or "You got a friend in you". They remove themselves when going to the next level/stage. They're not very common (also idk about the colors, they're kind of a place holder)

So scary.