Attack Actions and Attacks of Opportunity

[Hypersmurf]

Re: Sorry for the confusion

I am curious about one thing. Where in the rules does it state that an AoO can be anything but a "single melee attack." I know that disarm, trip, etc. act as a melee attack but then again (according to PHB page 137) starting a grapple "is the equivalent of making a melee attack."

Trip and Disarm don't "act as melee attacks", they are melee attacks. That's where it ends. If something is a melee attack, you can use it in an AoO. If it isn't, you can't.

For grappling, my take would be that it's impossible with an AoO because it requires moving into your opponent's square, and an AoO doesn't allow any movement, just an attack.

-Hyp.