Magic: The Gathering characters don't usually have overly long one-word names. At least, they didn't until 2021's Modern Horizons 2.
To explain that, we need to go to 1993 with Alpha. That year, a flavor text for Granite Gargoyle said the following: "While most overworlders fortunately don't realize this, gargoyles can be most delicious, providing you have the appropriate tools to carve them." - Asmoranomardicadaistinaculdacar, The Underworld Cookbook.
While the name of the cookbook itself has been lost to time, with Richard Garfield and co. coming up with the name seemingly on the fly, the name itself sort of struck a chord, and developers remembered it for later use. Asmoranomardicadaistinaculdacar was even referenced in a few other cards throughout the years, but creating a card based on it was shot down multiple times as the name was so long that it would crowd out the mana cost. As such, Asmor actually getting a card was a long shot.
But then came the set Modern Horizons 2 in 2021. A new card came up as a perfect fit. And, as a compromise, Wizards of the Coast kind of cheated on the mana cost by more-or-less including it in the rules text.
And that was it. An iconic card from 2021 used elements dating back to Alpha and came through to fruition largely due to a challenge in that no one could make a card after it. In a way, it's pretty ridiculous, especially since they broke common card convention. But on the other hand, they did do it, leading the way for other super long name cards in the future.
And, as for how to pronouce Asmoranomardicadaistinaculdacar's name and learn about her backstory, check out the video we did a while back on her: