Pickle Pee, Pump-A-Rum is an invisible crow atop the Firelink Shrine in Dark Souls 3. You might recognize the voice of Pickle Pee as she is voiced by Clare Corbett, who voiced Gwynevere and Priscilla in Dark Souls: Remastered and Alsanna in Dark Souls II.
However, in order to get to her, you would need access to Firelink Shrine first. After entering Firelink Shrine you must make your way to the bell tower behind the shrine. However, before you do that, you need to speak to the Shrine Handmaid and give her 20,000 souls (oof!) so you can unlock the door to the bell tower.
Fortunately, there’s a way to get to Pickle Pee without spending 20,000 souls by spending a lot of time trying to exploit a glitch of a tree hanging over the edge near the roof. However, if you don’t have the time and already have the souls then it might not be worth the attempt. After that, simply drop off a bridge to the roof of the shrine.
You’ll find Pickle Pee, Pump-A-Rum’s nest where you can open a trade list elsewhere and see what you need to drop in the nest to get what you want. Keep in mind, you can only drop or “trade” an item once each game day cycle. For example, in order to get 3 titanite scales from Pickle Pee you would need to drop in the Avelyn crossbow (assuming you don’t need it anymore).
If you want to grab a pair of iron leggings, you would need to drop a seed of a giant tree into Pickle Pee’s nest. The trade list for Pickle Pee has some pretty decent stuff from iron gear to the cool looking armor of the sun. However, in order to get that you would need to drop a Siegbräu in Pickle Pee’s nest. Make sure you pick one up along the way.
The Dark Souls Wiki has a wonderful list of items that can be traded and received in return:
|Item to Drop||Item Received|
|Firebomb/Rope Firebomb||Large Titanite Shard|
|Black Firebomb/Rope Black Firebomb||Titanite Chunk|
|Prism Stone||Twinkling Titanite|
|Loretta’s Bone||Ring of Sacrifice|
|Avelyn||Titanite Scale (x3)|
|Coiled Sword Fragment||Titanite Slab|
|Lightning Urn||Iron Helm|
|Homeward Bone||Iron Bracelets|
|Seed of a Giant Tree||Iron Leggings|
|Siegbrau||Armor of the Sun|
|Vertebra Shackle||Lucatiel Mask|
|Divine Blessing||Very Good Carving|
|Hidden Blessing||Thank You Carving|
|Alluring Skull||Hello Carving|
|Undead Bone Shard||Porcine Shield|
|Sacred Chime (any)||Help Me Carving|
|Shriving Stone||I’m Sorry Carving|
|Xanthous Crown||Lightning Gem|
|Mendicant’s Staff||Sunlight Shield|
|Blacksmith Hammer||Titanite Scale|
|Large Leather Shield||Twinkling Titanite|
|Moaning Shield||Blessed Gem|