Shame and horror fill your subconscious, and you never stop looking for ways to grant yourself the peace of the grave. Once per day, as an immediate action, you can make yourself the target of any attack originally directed against a creature occupying an adjacent square.
I'm playing an AC tank tiefling fighter in PFS, so this is an obvious fit.
1. When do I have to declare myself the target? Can I wait to see if the attack on my adjacent ally hits, or do I have to declare it as soon as the GM says who they're attacking? I could honestly see going either way on this one, but I'd probably lean towards the non-cheesy declaring it before the attack roll.
2. Since it just says the original target of the attack has to be adjacent, does this mean I can soak up hits from enemies that don't have enough reach to get to me? After all, it doesn't say I have to be adjacent to the enemy, or even within its reach. I see this as "I jump out in front, so part of my body is in the square with the guy being attacked", so I'd say that should work.
As mentioned, this is for PFS, so RAW answers only. No "ask your GM", since it'll be a different GM every time.