Ehwaz

How do you unlock Ehwaz?

In The Binding of Isaac, Ehwaz is unlocked by unlocking Head Trauma.

Creates a trapdoor leading to the next floor. Has an estimated 1/12 (8%) chance to create a trapdoor leading to a Crawl Space instead. Guaranteed to create a trap door to a Crawl Space if used on floor tiles containing certain patterns. Will not create trapdoors if used on the end floor of a challenge.