triping oneself?

[With a box]

Let's say we are falling.
If I can trip myself then I will be prone, dues I'm (teleported?)on ground without falling damage.
Am I right?

[Silva Stormrage]

I can't tell if this is serious or not but I believe you can just fall prone as a free action. Still if you are serious good luck getting this to pass in a regular game.

[eggynack]

Why would this negate falling damage? Falling damage originates from, y'know, falling, and you're not stopping yourself from falling. You're just falling in a different way, or, perhaps, falling with style. So, you're going to need some rules support for that one, far more than you've presented. You're also going to need some serious rules support for the idea that you can trip yourself in the first place, because the ability specifies that it works on an opponent, and while you could make some severe logical jumps to get to the idea that you're your own opponent, or the idea that you are an opponent, just to someone that isn't you, it's not a thing particularly supported by RAW. So, you're pretty much certainly wrong, and you'd need some crazy rules powers to get yourself to not-wrong.

[Ashtagon]

Quite often, the PCs are their own worst enemy. If that doesn't count as an opponent, I'm not sure what does.

(also, I'd throw books at players who try this)

[Crake]

Are you a winged flyer? If not, you can't be tripped while in the air, sooo..

Even being a winged flyer, getting tripped only puts you into a stall, which you can recover from anyway.

[eggynack]

Are you a winged flyer? If not, you can't be tripped while in the air, sooo..

Even being a winged flyer, getting tripped only puts you into a stall, which you can recover from anyway.
That is also an issue, and as I recall, the specific rule for winged fliers is that you take falling damage if the stall would necessarily place you in contact with the ground, which isn't exactly a good thing for this plan. This is an idea that has a whole mess of conflicts with the rules.