Pandaman is a joke character created by the author, Eiichiro Oda. He appeared hidden in nearly every One Piece chapter, episode arc, movie, and such.
Even though as a joke, Oda did give Pandaman some attacks as written in his datafile in the contest submission. His attacks are Bamboo Leaves Panda Drop and Giant Panda Deathlock.
Oda also mentions jokingly that Pandaman has a strength of “3,300,000 power” after eating bamboo and before meals.