Pooka is a baddie from Namco, debuting in Dig Dug and continuing on in many other Namco games, even going off into other franchises like Pac-Man. His most common attribute is that he inflates and deflates with various actions, and tends to explode when he is too big.
He appears in Pac-Man Universe as one of the most common enemies in the game, like Goombas in Mario franchise and Waddle Dees from Kirby franchise. They are enemies that come in many different sizes, but deflate with each hit. At their smallest size, they explode, damaging nearby enemies. This is the opposite of Dig-Dig, their debut game, where they grew with size each hit.