Shroomisaur
Smogon's fantastical fun-guy.
It's my favorite design thus far as well, I liked it immediately upon first sight. Honestly, it reminds me of a Heatran prevo (the way it's body is built is very similar to Heatran, sort of like a volcano. Those red rock highlights make me think it's Fire too, but could be misleading considering Nose/Probopass).I like the thing that looks like a cross between a nosepass and a metagross. I already want it, even if it turns out to be terrible.
My best guess at this point is Rock/Fire, but ugh, what an awful typing... like you though, I'd still use it even if it does turn out to be slow and have terrible typing.