What is an attack of opportunity?

[bradfhancock]

My friends and I have just started playing D&D 3.5 and purchased a lot of the books.

I was reading in the DM guide that some monsters can perform an "attack of opportunity".

I've read and read but I don't know how on earth to do one and what all it entails in regards to damage. Any help would be REALLY appreciated.

Also, I read that some weapons "threaten" an area around the character. I have a good idea what that means but I'm not 100% sure.

Thanks!

 

[MerricB]

The answers you want are in the Player's Handbook.

You can also find them here:
Attacks Of Opportunity :: d20srd.org

Cheers!

 

[Rune]

If you've got the PHB, your answers should be in the combat chapter, but the short answers would be:

...an attack of opportunity is an attack that someone gets because someone does something that triggers it within the threatened spaces. There is a pretty extensive list of things that trigger such attacks in the PHB, but the two main ones are making ranged attacks/spells or moving out of a threatened square. Which leads to the next question.

Usually, a creature's size determines reach (which, determines threatened squares), but some weapons also have a greater reach (and, consequently, threatened area.

An attack of opportunity manifests itself as a melee attack at the highest Base Attack Bonus.

Also, unless you have the Combat Reflexes feat, you only get to make one attack of opportunity per round.