Readers of the Tarzan novels may recall that Tarzan had a scar on his forehead (from a youthful fight with Terkoz the ape), as well as a tendency to get bonked on the head and suffer temporary amnesia.
What I learned only recently is that these aspects of Tarzan’s story appear to be based on the author’s own experience.
It’s funny that you mention Tarzan’s “tendency to get bonked on the head and suffer temporary amnesia”, because the first Tarzan book I read was Tarzan and the Jewels of Opar (which I have in common with Howard Zinn, who said that finding a copy in the street was when his “real education started”), in which Tarzan loses his memory for a good chunk of the book, and in which much of the plot development depends on his being disoriented about what’s going on and where his personality is closer to his childhood one due to not having memories from later in his life; because of its key importance, I was under the impression that the memory loss was a plot device that was specific to that particular book in the series.