Gatchapen is a penguin-based parody of the original Gatchaman character, originating from the Tatsunoko Production franchise. He belongs to the "Tachimals," a group where classic Tatsunoko characters are redesigned as hybrid animal beings, specifically combining penguin traits with Gatchaman's thematic identity.

As a Tachimal, Gatchapen possesses the defining species ability to freely change size, ranging from as small as a human front tooth to the size of an ordinary pet animal. He coexists within the Tachimals group alongside characters like Nyasshan (a cat-based Casshan), Piyotan (a chick-based Gold Lightan), Lunya (a cat-based Luna), Tekkuma (a bear-based Tekkaman), Churimar (a mouse-based Polymar), and Mach 111 (a dog-based Go Mifune).

Gatchapen's behavior reflects the series' comedic and lighthearted tone. He engages in slapstick situations and physical humor, such as playing golf where a bothersome bee provokes a wild swing causing him to spin like a helicopter. His portrayal remains consistent as a comedic, super-deformed penguin parody.