If a Blood Moon is in play and a Windbrisk Heights gets dropped, does the Hideaway trigger still happen?

I know that Humility, which looks a lot like Blood Moon, affects ETBs, but lands don't use the stack, so… does Windbrisk Heights enter as a mountain or as Windbrisk Heights?

I believe Windbrisk heights would enter the battlefield tapped, due to the static ability Hideaway grants. It enters the battlefield as a tapped mountain (due to blood moon changing it as it enters the battlefield), and does not trigger the “”When this permanent enters the battlefield, look at the top four cards of your library. Exile one of them face down…." portion of hideaway as the land no longer has that ability (due to blood moon).

I would agree with Jeremy.

With Blood Moon, any replacement effects – “enters the battlefield tapped”, “enters the battlefield as…”, “enters the battlefield with…”, etc. – will apply, since they're applied before the land is on the battlefield (and thus before Blood Moon has turned it into a Mountain). Any triggered abilities the land itself would have will not trigger, however, because after it enters the battlefield and the game looks to see if that event triggered any abilities, the land is a Mountain with no triggered abilities.

So Windbrisk Heights would enter the battlefield tapped, but the triggered portion of hideaway would not trigger.

Originally posted by Luis Viornery:

If a Blood Moon is in play and a Windbrisk Heights gets dropped, does the Hideaway trigger still happen?

no

611.3c Continuous effects that modify characteristics of permanents do so simultaneously with the permanent entering the battlefield. They don’t wait until the permanent is on the battlefield and then change it. Because such effects apply as the permanent enters the battlefield, they are applied before determining whether the permanent will cause an ability to trigger when it enters the battlefield.

305.7. If an effect sets a land’s subtype to one or more of the basic land types, the land no longer has its old land type. It loses all abilities generated from its rules text and its old land types, and it gains the appropriate mana ability for each new basic land type. Note that this doesn’t remove any abilities that were granted to the land by other effects. Setting a land’s subtype doesn’t add or remove any card types (such as creature) or supertypes (such as basic, legendary, and snow) the land may have. If a land gains one or more land types in addition to its own, it keeps its land types and rules text, and it gains the new land types and mana abilities.

It will still enter tapped though.

614.12. Some replacement effects modify how a permanent enters the battlefield. (See rules 614.1c–d.) Such effects may come from the permanent itself if they affect only that permanent (as opposed to a general subset of permanents that includes it). They may also come from other sources. To determine which replacement effects apply and how they apply, check the characteristics of the permanent as it would exist on the battlefield, taking into account replacement effects that have already modified how it enters the battlefield (see rule 616.1), continuous effects generated by the resolution of spells or abilities that changed the permanent’s characteristics on the stack (see rule 400.7a), and continuous effects from the permanent’s own static abilities, but ignoring continuous effects from any other source that would affect it.