Pipsnizzle the Thief, his Vault and the Mayor's ledger

Pipsnizzle, Hearthold's payroll goblin, runs through the Depths with a sack of borrowed loot. How to catch him, what he drops, and how to find his Vault.

Hearthold's payroll goblin has a black mask, a sack of 'borrowed' loot and excellent cardio. Now and then you'll spot him in a dungeon. Catch him before he opens his portal.

He appears on about 1 floor in 12, rarely in the very first dungeon, and a long dry spell makes him more likely.
Once spotted he runs, jukes and taunts, and escapes through a portal after 12 seconds. He drops a coin trail as he goes.
Stuns, freezes and roots turn into slows on him, and slows land extra hard (and shake coins loose).
Catch him: 12 gold piles, materials, a guaranteed item for your class (sometimes epic, rarely legendary) and more.
Now and then he leaves his portal open: follow him into his Vault, a hoard room with 10 chests and 20 coin piles. Its exit takes you down a floor.
He sometimes drops a page of Mayor Brammle's ledger. Find all 10 and bring them home for a reading, a title and a kiosk in the square.