Bonded Exoskeleton var addthis_config = {"data_track_addressbar":true};

Bonded Exoskeleton is a Tyranid Biomorph.

In 4th Edition, Bonded Exoskeletons come from ageing, and the older an organism the tougher its chitin. Various layers of bone, muscle and cartilage grow over various vital spots forming a sleek cover over the entire body. This makes creatures extremely tough and difficult to kill.¹

Sources

• ¹:Codex: Tyranids (4th Edition) (identical entry in Warhammer 40,000: Wargear p40)