they don't really have Kinder Surprise eggs in America. apparently some dumbass kid ate an entire egg a while ago, choked to death on the Surprise. So you don't see them around much.
but why would anyone ever eat a Ferrothorn, shit practically screams "DON'T EAT ME YOU MORON! I'VE GOT MORE SPIKES THAN THE ENTIRE BAND OF K.I.S.S! I'LL PUNCTURE YOUR ESOPHAGUS!"
love his sprite, though. How it spins around and such. Most sprite animations just kinda wiggle and jiggle, but they actually made Ferroseed do something cool. Grass/Steel is also a ballin' type combo. It's just a pity he doesn't learn Leech Seed by level-up, because then his awesome defense would actually be good for something. also, why the heck can't it learn Rapid Spin. that's messed up.
Design-wise, it could use a few less spots. otherwise, it's very reminiscent of ferrofluids, which are so amazing I'm going to quit writing this right now and spend the rest of my day watching youtube videos about them.