I have posted a note on Administrator ItsZippys talk page asking for help with a disruptive editor I realized yesterday that Mrm meets the criterion in that he is intimidating other editors making them reluctant to contribute to the article because heshe will undo their work and then engage in a long aggressive argument that generates walls and walls of text on the talk page yet fails to accomplish anything productive It has taken me four months to add  sentences and each one was a protracted battle with this one editor I have had no problems with any other editor even when we had different apparent backgrounds and perspectives