Chaos Burst

[SpiritReaper]

Trap
Activate only by Tributing 1 monster when your opponent's monster declares an attack. Destroy the attacking monster. Then inflict 1000 damage to your opponent.

Let's say your Raiza attacks my Sangan. I want to ativate Chaos Burst. How does this all resolve ? Can I tribute the attacked monster ? What's the damage ?

[SInge]

Raiza attacks.
You activate Chaos Burst by tributing any proper monster you control.
Opponent has a chance to chain in response.
Then you have a chance to chain in response.
Chaos Burst resolves destroying Raiza.
Raiza goes to the graveyard.
1000 effect damage is dealt to the opponent.

[Grengor]

You can tribute the monster that was attacked for the cost of Chaos Burst, because the attack has not resolved yet. For the events as you've listed them, here is how it plays out.

Player A: I attack your Sangan with my Raiza. I choose not to activate a Spell or Trap Card. Do you have a response?
Player B: I activate Chaos Burst, tributing my Sangan. Do you have a response?
Player A: No response. Drat!

Now the effect of Chaos Burst, Raiza is destroyed and your opponent takes 1000 damage.
Raiza's attack disappears, because he is no longer on the field to complete the attack, and you take no damage.
Now, after All of that, Sangan's effect will begin a new chain, and if your opponent does not respond with anything to stop Sangan's effect, you search your deck for a monster with 1500 or less ATK.

To sum up:
Chaos Burst tributes Sangan when you activate it. Sangan wants to activate, but has to wait.
The effect of Chaos Burst resolves, destroying Raiza and inflicting damage to your opponent.
Now Sangan's effect can activate, and you search for a monster.

There ya go. Enjoy the reading!

[SpiritReaper]

THANK YOU - all makes sense, I wanted to make sure.