Ambush/Xykon clarification needed

[Adeptus]

Having participated in a five player game I found myself pretty puzzled by the wording on the Ambush ability.

"...when this card enters play" was really confusing, since it never seemed to come up. Does the ambush happen the first time that creature is fought (as the card comes to the top of the stack) or only if that card is played as the top card?

I also found it a bit perplexing that Xykon is always on the top of his own stack, and that the dungeon collapse ends when he is defeated. From the comic, I'd have fought you have to fight a roomfull of people to get to him.

[Kumquat]

as to the ambush thing, I have thought that was the first turn it was played into a room, rather than when it comes to the top.

As to the Xykon thing, he is on top so he still gets all the support from the other monsters in the room and is significantly stronger from assistance. The rest of the fighting to get to him comes from the other 3 rooms that you must fight thru to get to him.

Again, for a more official answer I would suggest putting this in the rules questions thread...