mask of matriarch

So played the Matriarch the other day and had a question appear. Does the mask trigger off itself being played from the villain deck as the first card? We had gone through a flip and it was the card played for the villain turn, wasn't sure if it would play another card or not.

Nope, the Mask does not trigger itself when it is played, it was not in play when the trigger (a non-fowl card entering play) happened so none of the effects kick off.

But what about all the cards which trigger "When this card enters play"? 

I agree that a card which says "When this card enters play..." does trigger when it enters play, but the Mask doesn't have that type of trigger so I'm not sure what you're asking.

I just meant that clearly cards can have effects which are triggered by themselves entering play.  So since the Mask of the Matriarch entering play is a non-fowl villain card entering play, it seems like it should go off immediately.

On the other hand, there are some cards with effects that can only be in effect when they are not in play.  I guess it would be fine to say that a card effect cannot be triggered by itself entering play, unless it specifically triggers off of itself entering play...