Hello Mr Rosewater,
Un-rules question for you:Modular Monstrosity has the ability, "Whenever an opponent casts a spell, you have five seconds to choose a keyword you haven't chosen for a card named Modular Monstrosity today that's been printed on a creature card."There is also a ruling that reads, "If the keyword has a modifier, such as a mana cost or a number, you must choose a modifier that’s been printed."
My question is, can you choose a keyword that has been printed on a creature with a modifier that's only been printed on a noncreature card. Cumulative Upkeep has appeared on many creatures so is a valid keyword. Can I name "Cumulative Upkeep-Add {R}" which has only been seen on the noncreature Braids of Fire?
Thank you in advance

You have to choose a mechanic and a modifier that’s appeared on a creature.

Hi Mark, I'm going to my first Unstable draft this Saturday with my dorm. Am I going about it the wrong way by having my Spike combo prepared, bringing a Masters booster to Summon, having lists for Hangman and Modular Monstrosity?

That’s a good start. Do you wear glasses and if not, could you?

"You can’t do Mechanic X because X has to be defined. You have to do Mechanic [number]." Well, Fumiko, the Lowblood has an effect that grants Bushido X, Petrified Wood-Kin has Bloodthirst X, and Thromok the Insatiable has Devour X.

My answer was talking about keywords nameable by Unstable’s Modular Monstrosity.

With Modular Monstrosity, how does it work if you choose a keyword that typically has a number attached to it, such as Bushido? Would the number automatically be 1?

You have to pick the number and it must exist on a card. Then that ability regardless of the number is used up for the day.

If I create a token of Modular Monstrosity (That has no had no abilities named on it) with Feldon of the Third Path's ability, since tokens are not cards, if I name Trample would future tokens be able to name trample as well?

Any version of Modular Monstrosity, token or card, counts towards your named abilities for the day.

Can we call bushido X(Fumiko the Lowblood) for modular monstrosity and define X, or it has to be the same as Fumiko?

Choosing a keyword with X doesn’t mean anything as X is undefined.

For Modular Monstrosity, what is the definition of "today"? Does the list reset at midnight, or do you have to wait 24 hours before choosing a given keyword again?

It resets at midnight.

Re: Modular Monstrosity. The FAQ says that different protections count as the same ability and that you can't pick "protection from red" and "protection from demons and from dragons" the same day.

Oops. Being a Rules Manager is hard. I messed up. The FAQ is correct. You may not rechoose a mechanic that uses the same word . So Protection is limited to once a day as it repeats the same word. You can use islandwalk and mountainwalk because they are different words with a similar root.

You've said that Annihilator 1 and Annihilator 6 both count as an instance of the same keyword for Modular Monstrosity, but what about Forestwalk and Islandwalk? Do they count as separate keywords, or are they both instances of Landwalk? For that matter, what about Denimwalk? Is it also a form of Landwalk?

Here’s how it works. If the keyword name stays the same but just the number changes (Annihilator, Rampage, etc.), you can only name it once a day. If the name of the ability switches words (landwalk, protection, etc.) you can name each version once per day. In other words, if you say Annihilator 4, you can’t then name Annihilator 2 on the same day, but if you name islandwalk, you can later name mountainwalk on the same day.

If Modular Monstrosity dies, does it retain it's keywords, or does it lose them?

It loses them if it ever leaves play.