The crack in the center of the gully (aka the Terrarium Wall) to the left of Jungle Book.  Climb the obvious vertical crack through an overhang to the top.  Hexes and nuts work well in the irregularly-shaped crack.  Good horizontal placements for very small cams.  Large cams below and above the overhang.  Enjoy the exposure on jugs as you pull the overhang.  Descend from the rap station at the top of the gully.  

Named for the charming mud, moss, and millipedes characteristic of this section of Castellon.

In the center of the Terrarium Wall, to the left of the large left-facing open book.