Originally posted by penormasta

Lands: (60)

12x Plains

12x Island

12x Swamp

12x Mountain

12x Forest

You're welcome.

Wow, crazy that we both arrived at the exact same list!

Originally posted by Scipion

Since you guys don't seem to have a problem with adding older cards for a specific event, is there any chance we'll see a form of Cube show up? Even if it was a Pauper cube with Kaladesh+ commons it would be really fun.

Some cards are easy to add; they “just work” and we don’t need to do anything special to support them. Other cards take real work (sometimes a lot) to get working properly. Since Momir is a random and scattershot mode, it was fine to just add in whatever works automatically. Cubes, on the other hand, are artful and carefully constructed. Just using “whatever cards worked automatically” would make for a pretty poor one.

So we can’t really pull the same trick for a cube, but figuring out how to support cubes properly is something we’re definitely interested in. It’ll just take a bit more time and effort to pull that off than this did.

Older cards not in MTG Arena with high converted mana costs were added to the pool of cards that the Momir emblem can pull from. The abilities all work (though some aren't useful in a Momir context).

This was done in order to get a higher diversity of cards at higher converted mana costs to make the format more in the spirit it was intended. Impervious Greatwurm being the only 10 and Zacama, Primal Calamity being one of only three 9s was not the play pattern desired for this event.

Have fun! #WotCStaff

Originally posted by zeroGamer

Or they just added a few random high-cost cards for Momir so that you can't play the same creature indefinitely at high costs where there's only one or two creatures available in that mana slot.

^ This. These cards are just to add some spice to Momir at high CMCs; no connection to the new cards that will be added for Historic.

Originally posted by Muadahuladad

wait a minute, if it entered with haste it does not suffer from summoning sickness. removing the haste after it enters should not RE-apply summoning sickness

That's not how summoning sickness works - it's not a status that is added and removed from creatures. When determining if something can attack (or pay costs with the tap symbol), it can do so if you've controlled it since the beginning of your last upkeep or if it has haste (or some other ability that allows it to do so). Having haste doesn't have any lasting effects that persist when you remove it. #wotc_staff

Older cards not in MTG Arena with high converted mana costs were added to the pool of cards that the Momir emblem can pull from. The abilities all work (though some aren't useful in a Momir context).

This was done in order to get a higher diversity of cards at higher converted mana costs to make the format more in the spirit it was intended. Impervious Greatwurm being the only 10 and Zacama, Primal Calamity being one of only three 9s was not the play pattern desired for this event.

Have fun! #WotCStaff

Originally posted by girlywish

So do you think that the alternate cost abilities and the graveyard ability are even programmed in the game? They probably didn't bother, its just a 5/5 with extra flavor text

Yes, the abilities work. #wotc_staff

Originally posted by WotC_BenFinkel

I'll try to investigate this today. #wotc_staff

Solved it. I'll try to make sure it gets in for the ELD release. I'm really shocked this hadn't been found before as far as I know! The underlying issue was pretty complicated this time :/ ... #wotc_staff