What your actually witnessing in that video is an elaborate dancing ritual penguins use after they first kill and taste human flesh. When a penguin reaches maturity it must prove it is an honorable penguin and go on a long "mission" of sorts. When it returns it must do so bearing the head of one adult human being in it's beak. The penguin then buries the head in the sand and proceeds to dance in a seemingly irratic nature over where the head is buried. I can only now mourn for the poor person who met their fate at the hands of that "dancing" penguin.