Ran him a couple of times today (before the server reset).
He's in the same instance as Loot Pinata, except that you hang a right at the circular section of Vault. His trash are similar to the Pinata trash except they swell up and explode after 10sec once they've been brought down to a certain % health.
The boss has 4 of these trash as adds and they respawn if you kill them (which is inevitable). An offtank takes the adds and once every 30seconds or so, one of them gets 'supercharged' and explodes after 10seconds, wiping the raid. The DPS has to stop what they're doing and burn down the supercharged add before it pops. AOEing down before hand doesn't work because they return to max health when they get the buff.
The boss also does an aoe nova and chain lightning.
So basically it's a case of DPS the boss, kill the supercharged add when it gets the buff, don't get hit by AOE or link the Chain Lightning, collect loot.
Yes it is much harder than Loot Pinata.