This has nothing to do with certain feet that are happy. Although with the vibes they are playing, maybe a toe or two may twitch to the beat.
This was an idea born simply from the dual meaning of the penguins first part of their name; "Rockhopper". They are so called, as they live in an extremely rocky part of Antarctica, and so need to literally hop between rocks to get anywhere. However, rock is also a beloved music form I enjoy listening to. So, the two elements came together. And it was no surprise that the guitarist had to play the most well known guitar in the world.
There you have it. The power of music can move rocks (rockhoppers)!