Mana Drain Mana, A rules nightmare

[Limbo]

Is there a trigger that goes on the stack or does it just show up in your mana pool?

Wording: At the beginning of your next main phase, add X Mana to your mana pool, where X is that spell’s converted mana cost.

This means that is a obligatory triggered effect, that can be stifled.

In other words, do I have to declare that I have that mana in my mana pool and if I do not declare it then it is not there (until I end the phase, the trigger resolves, and I burn)?

As mentioned above, it is something that resolves automatically, even if not put actively on the stack.

[Gort32]

So, in other words, instants can be played without that mana even being in your pool before the trigger resolves, but at the point in time where you can play a permanent and/or a sorcery then the trigger must have already resolved?  So, if I play an Intuition at the beginig of my main phase and my opponent Power Sinks my intuition, I don't have to use up my Mana Drain mana?

(of course, this would be in bizzaro world where you can see Mana Drains and Power Sinks played at the same table...)

[epeeguy]

So, in other words, instants can be played without that mana even being in your pool before the trigger resolves, but at the point in time where you can play a permanent and/or a sorcery then the trigger must have already resolved?  So, if I play an Intuition at the beginig of my main phase and my opponent Power Sinks my intuition, I don't have to use up my Mana Drain mana?

(of course, this would be in bizzaro world where you can see Mana Drains and Power Sinks played at the same table...)

You could respond to the Mana Drain trigger with an Instant.  However, I would advise you to definitely be careful about what you say in this situation.  That is, whether or not you are responding to the Mana Drain trigger with the Intuition.  Because if you don't say that you are responding to it, then you could be in a rather grey area with this, especially when your opponent suddenly finds out that you have Mana Drain mana available to you and the Power Sink didn't get that mana.

[rvs]

In other words, do I have to declare that I have that mana in my mana pool and if I do not declare it then it is not there (until I end the phase, the trigger resolves, and I burn)?

As mentioned above, it is something that resolves automatically, even if not put actively on the stack.

That is a bit of a confusing statement. All triggered abilities get put on the stack. You might be confusing this with an acceptable shortcut.

[forests failed you]

Yes.  Since Mana Drain's trigger has to go onto the stack, whether or not both players have actively acknowledge it, it is assumed that it did and that both players passed priority thus allowing the trigger to resolve.

[epeeguy]

Since Mana Drain's trigger has to go onto the stack, whether or not both players have actively acknowledge it, it is assumed that it did and that both players passed priority thus allowing the trigger to resolve.

I'm not certain I would go quite that far, at least not without qualifying it slightly.  Again, as I initially noted, the DCI policy is that untargeted mandatory triggered abilities that do not have a choice on announcement (such as mode) don't have to be announced.  They are simply put on the stack.  The resolution, on the other hand, is going to be based on shortcuts demonstrated during the game and/or how players are playing.  And players do have to ensure their correct resolution.

Generally, yes, it will be assumed that the delayed trigger from Mana Drain is going to resolve automatically, as most people don't respond to it.  But, given that you can respond to it (for example, with Abeyance or Orim's Chant), then there may be times where you have to specifically say you are responding to the triggered ability.  Otherwise, you get into situations where intent has to be determined and the use of the shortcut previously has to be evaluated in light of the current situation.

So, it's not always going to be assumed that it did; just that based on how it has been played during the current game is how it is going to be assessed.  Not to mention what was said when the last spell or ability was played (as that gives a pretty good indication of whether or not the trigger had resolved).