Only pokemon of that type pairing I know of is Celebi (and not in that order).
So I guess I'm a synthetic copy of Celebi made by Team Rocket in an effort to replicate Celebi's time travel ability in their failure to capture a real one. It obviously didn't work so I'm a little strange around the edges, of primary grass instead of psychic due to my neutral origin and lack of will, and notably non-legendary.
Whether or not I have Time Travel capability remains to be seen, I haven't figured out how to use them if I do though.
Hey, man made elements could even account for that bit of Steel type that got nudged out by the more predominant grass and psychic.
Edit: My bad there is Exeggcute and Exeggutor but damn them I'm going with plan A.
It is waaay cooler.
(And some people think the original 151 are universally better then the newer generations.)