http://erischan2sqwddodpsehjymfn4ivcbj42rbmct4d5xwl4zlcsgzbdnqd.onion/eris/2.html?_escaped_fragment_=
For example, imagine a hobby website like a yoga page, which when a certain pixel is clicked under certain conditions, it opens up a secret chatroom with your handler.
Of course, the fnords were pords. Their carelessness, a long story shortened, resulted in systematic killings of dozens of CIA assets when Iran told other countries how to spot the fnords.