Gansan is a pile of three octagonal, brown, big rocks with black, Kirby-like eyes on the upper one.
Gansan attacks its enemies by rolling towards them. Gansan rolls faster when rolling down a slope. Its eyes transition from one rock segment to another when it moves (its eyes will keep shifting to the upper-most rock). It gives the Stone ability when it is inhaled.
Gansan's name is derived from the onyomi pronunciation for the Japanese word for circle/round, 丸 (gan); and the onyomi pronunciation for Japanese word for three, さん/三 (san), referring to how Gansan consists of three round rocks.