Sarah Rushman (Marrow)[]
Her skeletal bones seem to be more durable than normal, she had easily survived heavy hits on several body parts. For example, Flag-Smasher hit her twice with his mace on the head without creating much damage and Sabretooth threw her against a wall with no result on her inner bones. She also jumped off the Brooklyn Bridge twice without any major damage and being able to walk normally afterwards. Recently, this aspect of her mutant gift has been taken to ridiculous extremes once growing numerous bonespikes all over her body and then ramming headlong into an equivalent of a sky-borne albatross like a cannonball without much injury to her constructs.