Nice name, and after a bit of thought it goes fairly well with the flavor. I think it's properly spelled "trephination," but I could be wrong.

It seems like "trepanation" is an accepted spelling, but "trepanning" and "trephination" are preferred for purposes of disambiguation.

I think I'll leave it for now.

Curious effect. At first the "draws X cards" looks like a hefty drawback, if you're using this as a Jester's Cap effect to just make their library worse. But then I realised that if you're aiming to mill them to death, then this is milling them for 2*X, which is quite a lot. And then I realised it's actually very profitably pointable at yourself: strip out a bunch of excess land from your deck, and Mind Spring at the same time.

So... yeah, that's a nice design with versatility and subtlety :)

Thanks, Alex! I started out just trying to think of a way to color-shift Mind Spring into black for no particular reason, but then though about ways to make my original design more black. What's funny is that when you use it on yourself, it's actually a lot like casting three blue spells at once: Mana Severance, Selective Memory, and Mind Spring.