It's funny. For a long time I didn't think of "brown Grover" as being Grover at all. I just thought he was an anything monster that looked like Grover. This may have been because, in the early 70's, they were showing both old clips of the "brown Grover" and new clips of the blue one. Also, unlike Orange Oscar, I don't think there was ever a time when the brown monster was called "Grover". His voice was pretty different too. I knew that they looked very similar and could have been brothers, but the same guy? I just never saw it that way. Now, I realize that he was an early unnamed version of the same character.