mamegoma is a san-x character series first introduced in 2005. since its debut, the seals have appeared in a variety of san-x merchandise, games, and even picture books released in japan. The 2009 anime Kupū~!! Mamegoma! is based on the adventures of Mameta and his seal friends!

mamegoma appear as small, palm-sized seals, most commonly found in the colors white, blue, and pink (some variations, such as those featured in the LINE sticker sets, can be any color from purple to black). their name comes from the prefix mame, or "bean", meant as a nod to their miniature size. goma is taken from the japanese word gomafuazarashi, the japanese name for the iconic spotted seal (Phoca largha) so, mamegoma is the miniature spotted seal!.

from the san-x jp website:

Mamegoma is a small seal who was only discovered recently. Mamegoma is a palm-sized, miniature seal. Mamegoma is very friendly and, after getting used to you, will respond when called to or ride on your palm. There are many varieties.