In Wrath of the Lich King world bosses such as Doom Lord Kazzak were removed and they are being brought back in Mists of Pandaria. Today, Blizzard made a preview, describing one of the new world bosses in Pandaria, who's located in Valley of the Four Winds.

Boss description:

The ruthless saurok roam pandaria, stealing what they can and harassing the island's other inhabitants. The most infamous of these reptilian pillagers are Chief Salyis and his warband. For years, the saurok commander and his raiders have stormed through the Valley of the Four Winds atop Galleon, a collossal and well-armed mushan that is more a moving fortress than a simple mount.

Abilities

FIRE SHOT - Saurok Skirmishers riding on Galleon's back fire flaming crossbow bolts at random players inflicting Fire damage.

STOMP:

Galleon stomps the ground, inflicting Physical damage to players within 100 yards and knocking them down for a few seconds.

CANNON BARRAGE

Chief Salyis orders his minions to fire off eight powerful cannon blasts. Each blast inflicts Fire damage to players within 10 yards and knocks them back.

SALYN WARMONGER

Chief's Salyis's Warmongers periodically jump down from Galleon's back to engage players. The Warmonger uses an Impaling Pull to bring a distant target towards them and inflict Physical damage.

Here's also a killing video, so you can be prepared before it hits live realms!