Sanpei (known in English as Chim-Chim) is the pet monkey of the Mifune family in the Mach GoGoGo franchise who later appeared in Yatterman Night.
In the episode "Abareshi Prison", Sanpei is shown to have aged and is the only surviving member of the Mifune family. He guarded the Mach 5 in an abandoned shed that Galina and Alouette came across. He attacked Alouette for coming near it but then becomes friends due to her gentle nature. Sanpei allows Galina to use the Mach 5 and rides with them to break into Abareshi Prison to free the Doronbo Gang. Afterwards, Sanpei departs from the group and travels the world driving the Mach 5 by himself.