Which K-pop group was the first to create their own animal mascots?

Lately, it seems like having animal mascots is a big trend in K-pop — like BTS’s BT21 and Stray Kids’ Skzoo.

These mascots are really fun for fans since they represent the members’ personalities and give the group a unique identity beyond just music.

But I’m curious — which group started this whole mascot thing first? Anyone know?