Board Thread:Suggestions Forum/@comment-26149161-20150313214348/@comment-26149161-20150313221622

That is based off The Stairs of Cirith Ungol chapter, when Frodo sees the deadly flowers of Morgul Vale. Also, the water there would be steaming, and would give the same effects as the flowers, because Faramir warned Frodo to not drink any water from the area.