Can you Improved Grab on an attack of opportunity?

[Lhurgyof]

Just wondering, it's slightly important.

[Jarian]

RAW, not as far as I'm aware, as it requires a free action and you can't take free actions out of turn unless otherwise specified.

[Veyr]

You can make free actions as a part of other actions, and thus can used Improved Grab when you would otherwise be allowed to act — such as during an AoO. RAW, I say you can.

Note that the above argument is not clear-cut, and Jarian's reading is also valid; the rules are a bit ambiguous on this point, IIRC. In other words, ask your DM, not us — but I'd personally say yes, that seems to be part of the intention of the ability.

[Silva Stormrage]

I would say that you can. It would be similar to not allowing a target to use the knockdown feat on an attack of opportunity.

[Curmudgeon]

You can make free actions as a part of other actions, and thus can used Improved Grab when you would otherwise be allowed to act — such as during an AoO.
The problem with this reasoning is that an AoO is "no action" (see Rules Compendium on page 8). The RAW answer is that you cannot take a free action when it's not your turn unless there's an explicit exception (such as for speech).

[NeeL]

I know this is an old topic, But I don't think this hasn't got enough attention for those searching for an answer.

You can use any special attack that you can use as a melee attack as an attack of opportunity. That includes disarming, grabbing someone to grapple, sunder, or trip. - http://www.wizards.com/default.asp?x=dnd/rg/20041102a

Grabbing someone to grapple is precisely what Improved Grab does.

Also, let's look at a constrictor snake starting a grapple as an AoO:
- An enemy runs by. The snake wraps its body around the enemy to grab him (a normal grapple)
- An enemy runs by. The snake sinks its teeth in the by-passing enemy to get a grip on the foe before it wraps his body around him. (Using Improved Grab with its Bite)

The latter seems way more likely to me. That's why I would rule a Yes, you can use Improved Grab as an AoO.
But still, one should discuss this with his/hers DM.
Just hoping this puts things in a diffrent perspective.
Also, a squid or a octopus would have a really lousy AoO if it couldn't use Improved Grab.

[Gwendol]

As noted above, starting a grapple is an allowed AoO, and thus a creature with improved grab can use it as well. The only difference being that for a creature without this ability a melee touch attack is required, while for anyone with improved grab it's just a regular melee attack.

[Talderas]

The only difference being that for a creature without this ability a melee touch attack is required, while for anyone with improved grab it's just a regular melee attack.

Do you have those backward? I would think the melee touch attack would be part of improved grab while one without has to make a regular melee attack.

[Gwendol]

Short answer: no.

[Theoboldi]

Short answer: no.

Long answer: nooooooooooooooooooooooooooooooooo.

Anyway, since you can do a normal grapple as an AoO, and improved grapple isn't all that different, I'll throw in my hat with the other saying yes.

[Deophaun]

Just to make it explicit, both a regular grapple and a grapple initiated with improved grab require you to take a free action for the opposed strength check. There's no functional difference as far as AoO are concerned.