David Lengel is an actor. He played the role of Grassy Knoll Man in the episode Adam Ruins Conspiracy Theories. This article is a stub. You can help Adam Ruins Everything Wiki by expanding it. Retrieved from "https://adam-ruins-everything.fandom.com/wiki/David_Lengel?oldid=1589" Categories: Article stubs Cast Community content is available under CC-BY-SA unless otherwise noted.