Old man of the sea question

[Polynomial P]

My opponent attacks with two creatures. I block one with old man of the sea, then before damage tap old man to take control of his other creature. My opponent REBs the old man in response. Is the other creature removed from combat?

I would think the other creature is removed from combat. I gain control of it since the effect of old man should still go off, but then he regains control of it since old man is no longer in play.

[Rico Suave]

Relevant text: "T: Gain control of target creature with power equal to or less than the power of Old Man of the Sea as long as Old Man of the Sea remains tapped and its power remains equal to or greater than the creature's power."

If you try to control the other creature, and your opponent REBs in response, you will never gain control of that creature because when the ability resolves you will never satisfy the condition "as long as Old Man of the Sea remains tapped" since Old Man is no longer in play.

[Komatteru]

Doesn't last known information apply here?  When Old Man left play, it was tapped and had a power of 2.

[Jebus]

If the condition for the effect does not exist when the effect would begin, nothing happens at all.

418.3d Some effects from activated or triggered abilities have durations worded “as long as . . . .� If the “as long as� duration ends between the end of playing the activated ability or putting the triggered ability onto the stack and the moment when the effect would first be applied, the effect does nothing. It doesn’t start and immediately stop again, and it doesn’t last forever.

[Polynomial P]

Thank you. That is much clearer now.