Unlike other favorite Magic: The Gathering characters, Fblthp became popular pretty much out of nowhere.
Throughout the history of the long-running collectible card game, there have been characters who have had unexpected popularity. Syr Ginger from Eldraine became so huge after his first appearance that even the trailer for the sequel expansion had them, not to mention more cards. Squen and Cragg from the Lorwyn Eclipsed trailer have become so overflowing that many fans see them as modern mascots. There have also been misses, such as when Magic tried to make Loot a thing and dropped him as quietly as possible.
But the most famous unnamed card character to popular character has to be Fblthp. Pronounced 'Fibblethip', he started off as simply one humunculous on the Totally Lost card in Gatecrash in 2013, with his name only being seen through flavor text. As both artists and Wizards employees later said, they have no real idea how he became so popular overnight. But he did. A character being both ugly-cute and showing vulnerability probably helped.
Wizards was suddenly flooded with questions about the little guy. Totally Lost soon became a top reprint, and he soon became the perpetually lost character in cards. Many a Magic chatroom and forum in the mid-2010s were asking about the little guy, further putting Wizards on notice. Finally, by the time a return to Ravnica came around again with War of the Spark, Magic wanted to put out cards of a lot of past characters from the plane. And that's how Fblthp finally got his very own card.
Since then, he has remained a favorite character. While the planeswalkers and other character remain popular, with characters like Jace even being a leading man throughout many expansions, Fblthp takes the cake. He has the most individual character merchandise out there, keeps making random appearances, and, until Squen and Cragg came along, was the closest thing Magic had to a mascot. Even commons with Fblthp usually go for a few pennies because so many people collect the cards he is on.
Today, go to any Magic convention, and you'll still see the 'find the Fblthp' game going on and the costumed character on walkabouts. Go to Magic merchandise websites, and he's everywhere. And this was all because of one piece of art of a no name character that fans just universally embraced who has never been a major part of any Magic storyline.
You never know which character is going to be popular.
