In this modern view I like to keep things concise but personal: the egg cartoon most people mean is 'Gudetama', which originated in Japan and was launched around 2013 by a long-established character company. Its simple, lethargic design and short-format humor quickly spread through stickers, merchandise and brief animated segments not long after the initial debut.
I tend to think of 'Gudetama' as a cultural snapshot — an egg that reflects a weary, tongue-in-cheek take on adult life, rather than a purely cheerful mascot. Sometimes when I see it, it reminds me how small, relatable details in design can make a character travel far beyond its country of origin. That slim timeline — born in Japan around 2013 and becoming broadly visible within a year or two — is the core of where and when this egg-shaped phenomenon began.