This isn't quite right, but I wanted to see how the "lose 1 life" rider helped make things seem creepy.

(This could equally well be red.)

My mind's eye sees this as a looming monstrosity with glowing red eyes and it sending out a shock-wave when it steps. Flavorwise (in my interpretation) it seems bigger and red. I see
Thunderfoot Minotaur
Creature-Minotaur
When ~ ETBs, it deals 1 damage to target player.
4/2

It needs a different name to evoke the flavor. Maybe make it a Gorgon Minotaur and call it Death Glare Minotaur.

Hmm, yeah, Minotaurs have a bit too strong an association with red for me to be happy with them as a majorly black race in this set. A Gorgon with this flavour would be fine though.

Minotaurs are undeniably Greek in flavor, though. Am I wrong?

I agree they're Greek, but in Magic they're red. If we want black to be Greek mythology then I fear we do need to be somewhat selective in what Greek mythology we invoke; we probably need to steer clear of types that have a strong association with some colour other than black.

I think we can colourshift tribes if we decide it's appropriate in magic as well as history, but agree we shouldn't do so by default. I wanted to try this, but now agree it's probably not right in black.

I think we might be able to get away with a Rare Black Minotaur. It would evoke Greekness, but at the same time, show off that it is an exception to the rule. The ability on that creature would need to be very flavor driven, though.