You found your way here because either you’ve found an Eye of the Witness in Cult of the Lamb and don’t know what it’s for, or you’ve met Plimbo and need to know what he’s asking for. Here are the details.
Where to get the Eye of the Witness
The Eye of the Witness is an item you receive by defeating witness bosses. A “Witness” is essentially a stand-in for the Bishop (one of the four main bosses) once you’ve defeated them in a biome.
To find a witness, you simply need to make it to the end of a biome where you’ve already defeated the Bishop. Say, in Darkwood, if you’ve defeated Leshy, you need to re-enter the biome and make it to the end of the Crusade. Instead of finding Leshy again, you’ll fight a “Witness.”
I want to stress that you’re not looking to have a rematch. If you enter a portal to fight Leshy again, you’re not going to get the Eye of the Witness. You actually have to fight to the end boss.
Once you defeat a Witness, they’ll drop an Eye of the Witness on the spot. You just need to pick it up.
What to do with an Eye of the Witness
Once you have an Eye of the Witness in hand (ew), the next step is to find Plimbo. You meet Plimbo in Anchordeep in the same way you meet most of the NPC shopkeepers. You simply need to adventure around until you bump into them. That is to say, meeting them is random, so you just need to keep running Anchordeep and making sure you explore everything and eventually you’ll meet him.
Once you meet Plimbo, he’ll go to a place on your overworld map called Smuggler’s Sanctuary. From there, he’ll exchange any Eye of the Witness for a Holy Talisman. That, in turn, can be traded for a new fleece.
Note that you can only gain four Holy Talismans despite eight Eyes being available in a playthrough. You can gain four Eye of the Witness before fighting The One Who Waits, and four afterward. However, Pimbo will only part with four Holy Talismans in total.
