Ravenous Trap and dredge

[arj]

The oracle test for Ravenous Trap:

"If an opponent had three or more cards put into his or her graveyard from anywhere this turn, you may pay 0 rather than pay Ravenous Trap's mana cost.
Exile all cards from target player's graveyard."

I'm wondering if opponent discards Narcomoeba, can I then cast Ravenous Trap to make Narcomoeba not come into play?

A related question, lets say that opponent has Ichorid in graveyard, and then responds to the trigger by dredging. Related to the first post, is there a way for me to place my trap so that opponent loses both ichorid and the 3 cards discarded, meaning before it comes into play?

Given that my opponent has discarded 3 cards this turn and has returned ichorid, is it possible for me to play trap after he puts ichorid into graveyard to blow his whole yard?

Thanks

[Meddling Mike]

I'm sure Clariax can confirm, but the answer to both questions is yes.

Narcomoeba hits the graveyard and the triggered ability goes on the stack, with this ability on the stack you can cast Ravenous Trap to exile Narcomoeba and fizzle the effect.

Similarly, Ichorid's triggered ability needs to be placed on the stack. You can cast the Ravenous Trap with this ability on the stack and once again it will Exile the Ichorid. This happens independently of the Bazaar activation, but if your opponent were to activate Bazaar that effect should resolve and meet the conditions for the trap effect at which point the Ichorid's ability would still be awaiting resolution and give you the opportunity to Ravenous trap.