Lobotomy and grind don't seem like a good name match. Is this overcosted? I mean, it is sort of "Nerf a creature" but it's also usable on your own if you want to make milling your strategy. Which, huh, this multiplies until it hits a land. So grind15 is game winning... reasonablty potent.

Black getting beserk? Hmmm, I can see it. Though it isn't mqde explicit in your new colour wheel.

I'm guessing amuseum tried to keyword mill as grind, ignoring a) that there is zero flavor connection, and b) that grind is already slang in real Magic

It's documented in the 'mechanics' link up there ^

That's a really dumb mechanic then. There's a reason Wizards didn't use it during RTR block