What Is A Domo / Domo-kun?

Domo-kun is a small brown open-mouthed monster (hatched from an egg) who lives with a wise old rabbit underground and really, really likes TV. Domo-kun is the mascot of NHK's BS2 (a satellite channel in Japan; he also appears on BS1).

Sources; http://www.urbandictionary.com/define.php?term=domo-kun