What happens if a creature has no toughness defined?

Question

Dominaria introduced Merfolk Trickster, which causes a creature to lose all abilities, without setting a power and toughness.

What happens if a card such as Tarmogoyf loses all abilities?

Would Tarmagoyf become a 0/0 in this case, because a number not defined is treated as 0? Or would it possibly be a 0/1, because the printed toughness on the card is "*+1", and only the "*" part is undefined? What about a card like Boneyard Wurm, would it just become 0/0 (and thus die)?

There seems to be a possible contradiction between the comprehensive rules and the Gatherer rulings. The Gatherer rulings say:

If the target creature has power and toughness written as / with an ability that defines its power and toughness, it’s 0/0 when it loses all abilities. If its power and toughness are written as */*+1, it’s 0/1, and so on.

Rule 208.5 deals with this situation:

208.5. If a creature somehow has no value for its power, its power is 0. The same is true for toughness.

It seems to me that a Tarmagoyf that loses all abilities has no toughness defined. It's toughness is written as "*/1+*", which according to 208.2, its toughness should be defined by its abilities.

So, while it is clear that a */* creature will be a 0/0 if it loses all abilities; what happens to a */*+1? Is it 0/0 or 0/1?

Also, I find it interesting, though not likely relevant, that Tarmogoyf is written "*/1+*" (with the 1 first), while the Gatherer ruling references cards that are "*/*+1" (with the * first).

Answer 1

With the introduction of Vehicles in the set Kaladesh, this situation is now possible and explicitly covered by the rules.

208.5 If a creature somehow has no value for its power, its power is 0. The same is true for toughness.

Answer 2

This question is hypothetical and not covered by the rules. All current cards which cause a creature to lose all abilities also set the power/toughness of the creature, or cause it to no longer be a creature making the power/toughness irrelevant.

It's a safe bet that loses all abilities cards are designed that way to avoid this conundrum.

Answer 3

Tarmogoyf will be a 0/1 in this case.

As long as Tarmogoyf is missing its characteristic defining ability, the only information available for determining its power and toughness are the */*+1 printed on the card. So, it's not exactly accurate to say that it has no value for it's power, but rather, it has a value determined by an undefined symbol, and a calculation involving that symbol. In that case, rule 107.2 applies:

If anything needs to use a number that can’t be determined, either as a result or in a calculation, it uses 0 instead.

Since the start symbol has a value that can't be determined, the Tarmogoyf's power and toughness are evaluated as 0/1+0, or 0/1.

Similarly, Boneyard Wurm's power and toughness is printed as */*, which would evaluate to 0/0 while it has no abilities.

Answer 4

There have been no printed cards that remove static abilities without also setting the power and toughness (Snakeform, Ovinize) or changing the card to no longer be a creature (Soul Sculptor) as stated in ghoppe's answer.

Tarmogoyf's ability which sets its power and toughness is in a special class of static abilities called characteristic-defining abilities [CR 604.3] which function in all zones and even outside of the game. Any hypothetical card which exclusively removed static abilities would need a special ruling on its interaction with these type of abilities.

Asterisks * representing power and/or toughness are treated as 0 (even within calculations) in the case of static abilities that create replacement effects [208.2b] and also characteristic defining abilities when the value of the asterisk cannot be determined.

In addition to these definitions, Gatherer also treats asterisks as zeros with constants added continuing to be added. To find Tarmogoyf in Gatherer by Power and Toughness alone, one must set the search parameters to Power=0 and Toughness=1.

It is reasonable to assume that any future ruling would be consistent with this and set completely undefined asterisks to zero, although this is just speculation on my part.

If we assume that the above proves true then we can make the following conclusions regarding the specific creatures mentioned in the question. - If Tarmogoyf somehow lost his ability which defines the value of *, then each * would be taken as equal to 0 so that it would become 0 / 1+0 => 0/1. - Boneyard Wurm would become a 0/0 and thus under [CR 704.5f], be put into its owners graveyard. (Of course, once in the graveyard its power and toughness would be reset based on its characteristic-defining ability)

The rulings for Nightmare help clarify some of the interactions with asterisks in power/toughness.

If you control 0 swamps, then the Nightmare has 0 toughness and will be put into its owner's graveyard as a state-based action right before the next player gains priority.

Nightmare's power and toughness changes as the number of Swamps you control changes.

The ability that defines Nightmare’s power and toughness works everywhere, not just on the battlefield.

EDIT

[CR 208.2a] in reference to Asterisks in Power and Toughness

This ability functions everywhere, even outside the game. If the ability needs to use a number that can’t be determined, including inside a calculation, use 0 instead of that number.

Example: Lost Order of Jarkeld has power and toughness each equal to 1+*. It has the abilities “As Lost Order of Jarkeld enters the battlefield, choose an opponent” and “Lost Order of Jarkeld’s power and toughness are each equal to 1 plus the number of creatures the chosen player controls.” While Lost Order of Jarkeld isn’t on the battlefield, there won’t be a chosen player. Its power and toughness will each be equal to 1 plus 0, so it’s 1/1.