Pretty straight forward topic, here is my idea. The Maiden- A female boss infected which has spikes (made of bone) piercing through her skin, she can "hug" a survivor which then leads them to getting stabbed with the spikes. She can hide in closets, unopened doors, or can just appear randomly. She is silent most of the time, you can only tell if she is in a closet, or a unopened door by the sound of her spikes rubbing against the door itself. Her speed is that of a normal survivor, so your chances of survivng an incounter with her is fair (depending on the situation).