Cool design. Might need the "if you do..." rider checking the sacrifice, just so you dont get awkward questions when you sacrifice nothing.

Fun fact: If you don't have an Ornithopter or similar 0cmc artifact in your graveyard and this is the only artifact you control and it deals combat damage to a player, you don't need to sacrifice it.

Since the triggered ability has no legal target it is never put on the stack.

Also a fun fact: You need time travel owers to resolve this ability.

#EvilDesignsThatDontWork

Oh yeah...

> Also a fun fact: You need time travel owers to resolve this ability.

Is this another issue you are referring to, but not telling us outright?

Oh, sorry, I assumed you'd get this one since I make this reference a lot to describe this kind of mistake.

Scenario:

• You control this and two artifacts with different converted mana cost, let's say Glass Golem and Stonework Puma.
• In your graveyard you have Ornithopter and Birthing Pod.
• You trigger the ability.
• We assume you want the awesome synergy with Birthing Pod on the battlefield and intent to sacrifice the one available Glass Golem to do so.

Now, what happens?

• You put the ability on the stack, as part of doing so you choose, you choose targets. Here you need time travel, because the targeting restriction includes knowledge about "sacrificed artifact's converted mana cost". You haven't sacrificed an artifact yet.
• Assuming you have chosen Birthing Pod now the ability is on the stack. Players may respond e. g. by using Shatter on Glass Golem.
• If all responses are handled, eventually you resolve the ability. Now you go through the motions and start with sacrificing an artifact. Your highest cmc artifact is Stonework Puma, so you do that. But wait! The targeting restriction says you needed to choose an artifact card with converted mana cost less than Stonework Puma. And the restriction applies both when choosing targets and when resolving the ability. This is an alternative point where time travel to correct your choice of target would be helpful.

The rules covere choosing an illegal target and want you to roll back to before casting the spell - tournament rules might have something to say here as well about maintaining the game state.

Even if rolling back the game state was a solution information has been made public (over your opponent's Shatter, but imagine the added complexity if they (or you) had used Shape Anew).

p.s. A general rule of thumb is that in addition to working through a text in order every instance of "target <foo> [with <characteristics>]" means that you have to be able to start your ability by writing down "choose target <foo> [with <characteristics>]" at the beginning of the ability without creating a time paradox.

That goes somewhat over my head. Does this still apply to this "if you do" variant that I changed this into 4 hours ago?

Don't think so, no. Now it's just a weird enabler for artifacts with ETB effects.

I don't think there are many of ... oh shit. Modular. BAN!

Yes, it does. If you choose a target (even if its optional) you need to know at the time you put the ability on the stack whether the target is legal. (If its optional you have to be able to look into the future to determine whether you can take the option.)

To illustrate. Your text is equivalent to:

> Whenever Raving Wright deals combat damage to a player, choose up to one target artifact card with converted mana cost less than sacrificed artifact's converted mana cost in your graveyard. Sacrifice an artifact. If you do, return the targeted artifact to the battlefield.

Functionally identical, but no longer obfuscating the order of operations. Whether you sacrifice an artifact or another (or none at all if all your artifacts including Raving Wright are removed in response to the ability) does influence the later operation on whether you can return an artifact and which, but every time you use the word "target" the conditions also have to be checked long (as in priority is passed between events even if real-life it can be less than a second) before the ability starts resolving.

TWO STEP CHECKLIST: 1. If you use information that is not available until an effect resolves you cannot require choices based on that information before the effect resolves. 2. All targets are chosen before a spell/ability starts resolving.

Always. That's the whole point of targets. It's so your opponent can Lightning Bolt in response to your Giant Growth and you cannot switch around to your other Grizzly Bears. You are committed, but you always need to know what you can commit to.

That's why sometimes cards have weird wording to make certain information that is usually only collected during resolution is checked in earlier during casting already: Jaws of Stone has these last six words, because the number of Mountains in other similar spells (that always affect only a single target) is counted during resolution. But since the number also affects the number of targets during casting it needs to be taken from another point of time.

There are at least two solutions - both make functional changes, obv:

• Target the artifact to be sacrificed as well. If you do so, there is now a contract during casting that makes it so you know already which artifact is planned to be sacrificed. Here the "if you do" makes certain you don't weasel out of the contract and still collect your reward, but if you have no reward anyway, you still can weasel out of your mandatory payment by sacrificing the targeted artifact e. g. to Arcbound Ravager. The other functional change is that you cannot reconsider after commiting to the target. If you really want that Birthing Pod and have two Glass Golems ready, your opponent can Shatter just the one you targeted and you cannot sacrifice the other one, because you already committed while putting the ability on the stack.
• Don't target the artifact with all the time-sensitive restrictions. If you do not have to choose a target, then you can use the order of effects as written in the abilities text to establish in which order information is generated - and during resolution the artifact is sacrificed before the artifact card is chosen and returned, so the required information exists. The functional change is that you can surprise your opponent with your choice of artifact you return - maybe a spell they cast in response changes the board state so that you need a sudden flying blocker and you reconsider to pick the Ornithopter instead.

(NOTE: I noticed that I used "cast" rather than "put the ability on the stack" once and corrected it; the ability was so complex that I sometimes forgot it was not a spell like Shape Anew, but more like Shape Anew on a stick. If I missed an instance of using cast incorrectly in this way, please mentally correct it. :))

So... No targeting on the last effect and we're all good?