Kirigami, the cutting and folding of sheets, creates three-dimensional shapes from flat material. Known for centuries by artists and the subject of recent research, practical application of kirigami is limited by the complexity of the folding step. One kirigami pattern, a series of staggered slits, has been used for expanded metal gratings and packaging material. Because it deploys with simple tension, not complex folding, we call it Tension Activated Kirigami (TAK). In this paper, we introduce a new TAK pattern that drives flat material into rows of vertical, accordion-like, folded walls. This array of walls has a stiffness and strength comparable to a full honeycomb core, yet it self-deploys under tension. The structure is also conformable, allowing it to wrap around objects. These attributes enable a new paradigm for low-cost structural panels and a sustainable alternative to plastic cushion wrap.