Pompompurin was first introduced at 1996 on "Tamagotchi m!x."
Tamagotchi m!x (たまごっちみくす Tamagotchi Mikusu) (pronounced "Tamagotchi mix")
is a range of Tamagotchi devices initially released in Japan on July 16, 2016.
Pompompurin was created through an in-house contest held by Sanrio in 1996 to design a new dog character.
His design was the most popular and ended up winning the contest.
Sometime after the contest, he debuted in the 1996 July issue of Strawberry News with his original name being My Pudding,
but it got changed later on to his current name.