The Pump Drago is an unused boss found in Mother 3. Its battle theme is Strong One (Masked Man). Little is known about what part it would have played in the story, much less in general. Its sole attack involves bursting out into laughter and randomly attacking one party member, even though the animation shows it throwing 3 bombs (as if the attack was still being tested). Its outside sprite is Mr. Pump, indicating that it was most likely intended to be a boss in Chapter 7.
It uses the same battle sound as Masked Man which is not one of the 60 enemy battle sounds but is Claus' Instrument 4-3 which falls under Code Number 289.