I'm currently (re)reading Moorcock's The War Hound and the World's Pain. Short synopsis - an educated, cynical, apostate and unapologetically brutal mercenary in the Middle Ages is recruited by Lucifer to recover the Holy Grail, nominally so that Lucifer can wheedle his way back into God's good graces.
He's told to start by finding and talking to a hermit named Philander Groot, which he does. He turns out to be something other than a stereotypical hermit.
"You don’t look like a hermit.” Sedenko put his hand on the hilt of his sabre and strode forward to inspect the apparition.
“Sir, I assure you that I am, indeed, a hermit.” Groot became polite. He was distant.
“We heard you were a holy man,” Sedenko continued.
“I cannot be held responsible for what others hear or say, sir.” Groot drew himself up. He was somewhat shorter than Sedenko, who was no giant. “I am the same Philander Groot for whom you were looking. Take me or leave me, sir. This is all there is.”
“We had not thought to find a dandy,” said I, by way of apologizing for Sedenko’s frankness. “We imagined someone in homespun cloth. The usual sort of garb.”
“It is not my way to fulfill the expectation of my fellow creatures. I am Groot." (emphasis mine)
Granted that there's no seeming connection between any of that and Marvel Comics, and no similarity between the characters, that simple declaration "I am Groot." really leaped out at me as at least an odd coincidence.