Was this in response to the glass cannon idea? I kinda like it... maybe I'll make a silly literal glass cannon too.
My skills at drawing, are sub-par; I haven't used paint for a very long time, and paint wasn't particularly co-operative, but I tried. Unfortunately, I drew the thing in a pose from behind, so the eye (that black thing in the middle that, if it had a cross instead of being completely black, would've been a scope) is unidentifiable. Originally I was going to have it with four legs, but I had trouble picturing how it'd move quickly, so I decided to add in the purply-orange stuff at the last minute and say that the legs were mainly to dig in whilst it attacked.
@ Lofty: I'm liking the meteor idea, the scene with lucario makes me wonder if maybe this pokemon's true claim to fame will be access to all of the "overheat" moves. =D Had you considered making the rock eyelids closing horizontally, perpendicular to the way human eyes close? Tiny tweak but it might make it look more alien and less cute. =P