Just wondering if you have ever seen this figure before?
I've had it since I was a kid in the early 80's, and it's always lived with my lego (which was mostly hand-me-downs from my older brother - ie Space #897 rocket set). It doesn't fit with Lego, but does seem to fit with Duplo.
Looking at early Duplo mini figures, they look vaguely similar, however the Duplo figures are squared off, whereas this figure's body is circular.
There's no markings to indicate brand...
Just a little mystery in my life. :)