First appearance: From Hell It Came (1957)
Nuclear radiation turns a prince who was executed when he was wrongly accused of murder and buried in a hollow tree stump into a revenge seeking walking tree known as a Tobonga. The Tobonga goes on a rampage killing everyone who gets in his way including the guy who actually committed the murder. Can anyone get close enough to drive the knife protruding from the monsters chest all the way through the monster's heart thus killing it?
I don't think there's enough monsters nowadays that are the result of radiation and revenge.