Grubb Idol - Find the hidden Grubb Idol - Trophy/Achievement.
After rescuing Eugene Ius and heading down the catacombs you will discover a Stone Native Village. Soon as you progress further you will see a hole in the wall boarded up by fences. The grubbs hint that they know the Grubb Idol is there but they hope you won't find it. Shoot the fences down with the Zappfly to break the fences boarding the wall then drop down and head to the rope to climb up to the roof. After that there is a second rope. Climb up to that rope too then double jump into the hole and the Grubb Idol is inside. Grab the Grubb Idol and the Grubb Idol Trophy/Achievement is yours and will unlock after grabbing it.