The Defense Advanced Research Projects Agency, or DARPA, has envisioned some peculiar and diverse projects over the years, from molten metal-filled missiles, all the way to submarines that can fly. Then there’s this new project that aims to create a portable cylinder that can blow up into a nearly impenetrable wall. Because sometimes you just need that. The group suggested the idea, which is nicknamed Block Access to Deny Entry (BlockADE), in a request for information that was spotted by io9. In short, it asks for a way to “construct a barrier without human intervention,” meaning no touching anything. You just hit a button, or pull a tab and it should expand into a barrier that DARPA says would be “orders of magnitude” in size. That barrier would then need to keep — or at least slow — somebody from getting through it using a saw or other hand tool.