CMC: Converted Mana Cost? Christian McCaffrey? One of these other things (https://en.wikipedia.org/wiki/CMC)? Nope, it's the Conditional Morph Cube!

Each player has an emblem (better wording TBD): "Cards in hand can be manifest for as a sorcery, played as a Wastes, or played as a tapped basic land of any of its colors."

Some cards are considered "good," so we tend to see them in many formats, including Cube. Many cards are "bad," so outside of their retail limited environment we usually never see them again. Now there are certain "worst cards" cubes, but I'm not interested in playing cards like Zephyr Spirit or Sorrow's Path that are just straight bad.

But I am excited to play powerful cards with high ceilings in Magical Christmasland but in the Real World are just too damn conditional. The cards that have never even heard of Quadrant Theory. Where "living the dream" often means just getting them to function at all.

Ok, but if we jam a bunch of these conditional cards together in a cube, won't we just have one big mess? Yes, but now we get to the 2nd word of the cube: morph (technically manifest, but "morph" sounds nicer). Sometimes we set up the dream; sometimes we must defer the dream and take the morph instead.

And finally while we're at it with the emblem business, drawing the right combination of lands and spells is so passé. That's why the emblem also allows us to play any card as a Wastes or a tapped basic land of any of its colors. So you might struggle to actually cast Niv-Mizzet Reborn, but at least you can have an Uncharted Haven to help cast your other spells. Decimate may miss its targets but can act as a tapped Mountain or Forest.

Do you ever agonize over your last cuts, puzzle over your fetch/dual nonsense color requirements, then just wing it anyway? Do you ever look at your draft sideboard, waffle over some minor potential swap that probably won't matter, then decide to just ship it? Now you can craft your manabase no worse than Frank Karsten and sideboard no worse than PVDDR, because every drafted card goes straight into your deck. No deckbuilding, no sideboarding, no muss, no fuss.

While we are living the "easy modo" life (there's a reason it's not called "easy MTGO"), tokens and counters can also be such a pain. So as a bona fide bar cube, you won't have to deal with any of that with the Conditional Morph Cube. But very occasionally you will have to deal with counters (as in counterspells) and even shuffling, like when you get hit by Settle the Wreckage and fail to find. ;)