The danger dog is defined by the bacon, and specifically by what the bacon does on a flat, screaming-hot cart griddle: wrapped tight around the frankfurter, it renders, crisps, and effectively fries the dog in its own fat as it cooks. This is the whole sandwich. A bun, grilled onions and peppers, a stripe each of mayo, ketchup, and mustard are the frame, but the bacon wrap is the part that makes it itself. It turns a boiled-or-griddled sausage into something shallow-fried in pork fat, with a salty, crackling exterior the dog could never develop on its own. The name comes from where and how it is cooked, on an unpermitted cart on a Los Angeles sidewalk after a show, and that context is inseparable from the food: this is street cooking, fast and hot and slightly outside the rules by design.
It works because the cart griddle is the right tool for exactly this build. A flat plancha lets the bacon-wrapped dog sit in continuous contact with the heat, so the fat renders evenly and the wrap fries crisp rather than steaming the way it would on a grill grate. The peppers and onions are cooked on the same surface in the rendered bacon fat, which seasons them and ties them to the dog. The bun is split and laid face down on the griddle to toast and to soak a little of that fat, so it can carry a heavy, greasy, fully loaded dog without falling apart in a hand on a crowded sidewalk. The three condiment stripes are the cool, acidic counter against a sausage that has been wrapped in pork and fried, applied fast and loose because the whole sandwich is built to be made in under a minute and eaten standing up.
The variations stay close to the cart. The plain build keeps it to bacon, dog, bun, and the three squirts. The loaded build piles on grilled jalapenos and a heavier bed of onions and peppers. Each of those deserves its own article rather than being crowded in here.