What's the real benefit of the feat Owlbear Berserker?

Question

The benefit of the feat Owlbear Berserker says

When grappling, you can make an unarmed attack to deal 1d6 points of normal damage with a successful grapple check. You do not suffer the usual −4 penalty for dealing normal damage. (Unapproachable East 44)

What does this feat's benefit allow a creature to do?

Here are some readings.

• The benefit only increase the creature's damage dealt (and eliminates the creature's penalty) when the creature takes the action Damage Your Opponent. That is, the benefit, essentially, improves the creature's (presumably lousy) unarmed strike damage.
• Each time the creature makes a successful grapple check, it can make an unarmed strike (at a −4 penalty) that deals 1d6 points of damage (as per Attack Your Opponent).
• While grappling, once per attack (or, alternatively, as a standard action) the creature can make a grapple check; success means the creature can take a free action to make an unarmed strike that deals 1d6 points of damage. Note: The least likely reading, but nonetheless possibly useful if the creature also has the extraordinary ability constrict.

The feat is unmentioned by the D&D Frequently Asked Questions, and Unapproachable East's errata has one entry (it's not for this feat). The feat is rarely mentioned: for example, here as an unattractive feat for a barbarian and in this Project Gutenberg collection of owlbear ephemera. The feat doesn't seem to have received further analysis. As an official ruling is unlikely to come to light, careful textual analysis is preferred over house rules and speculation.

Answer 1

It's option 1. The feat's wording mirrors the Damage Your Opponent wording, to the point of being a direct edit of it:

While When grappling, you can deal damage to your opponent equivalent to make an unarmed strike. Make an opposed grapple check in place of an attack. If you win, you to deal nonlethal normal damage as normal for your unarmed strike (1d3 points for Medium attackers or 1d2 points for Small attackers, plus Strength modifiers) with a successful grapple check. If you want to deal lethal damage, you take a You do not suffer the usual −4 penalty on your grapple check for dealing normal damage.

There would be even fewer strike-throughs, but they moved around a couple of clauses (making dependent clauses follow instead of precede, which is admittedly cleaner writing), and made the odd choice to call it “normal” damage instead of the normal “lethal” damage.

There much less to rest an argument for any other option on. It can't be the second option, because the feat is not worded as a single-point trigger — “when grappling” is not the same as “when you grapple”!

It can't be the third option — as you note it's the least likely — because given a straightforward alternative (option 1) that requires fewer assumptions and fewer additions of unmentioned procedural steps, basic logical principles require rejecting such a reading unless firm support can be found that makes it the overwhelmingly more likely reading.

So in conclusion, the real benefit is threefold: you do generally better damage, it's lethal instead of non-lethal, and it's an effective +4 to hit with it.