King Ping is a slightly larger penguin that can usually be found around Scalawag Point. He is noted to be one of the hardest Northrend mobs to find, despite having a less then 12 hour spawn rate (confirmed), as players are often doing the Kalu'ak daily quest which takes place directly where he spawns, so he doesn't stay unslain for long.
King Ping is a criteria of the achievements:
King Ping's name likely comes from the word Kingpin, a high ranking official. The "Ping" part could just be there to make it rhyme or it could come from the children's television show Pingu which stars a clay penguin as the main character. The "Ping" part could relate to how penguins resemble bowling pins. The entire name King Ping might be a reference to the fictional giant gorilla King Kong who had a similar relationship of size with real-life gorillas as King Ping has to penguins, though on a larger scale. He also might be a reference to the recurrent boss from Nintendo's Kirby games, King Dedede, who resembles a large penguin.