OK, switching ideas.

Would a magical chain work? As a weapon, she would hold a bundle of chain in her hand and swing it around to flay or whip opponents, but its special ability is to have multiple chains fly out of the cracks in her armor and form a spiderweb-like chain-link fence creating an immovable physical wall protecting those behind her. In this mode, she is part of the wall and cannot move, the wall is also not airtight so small things, fluid things or energy(like fire and heat) can still pass through (it also attracts lighting, ouch). The chain call also all be retracted back into the armor, providing extra armor in the form of chainmail. It's just a very physical, almost brutish type of weapon, but I want something with a defensive, physical aspect, but still unique and imaginative enough that I can play around with it.