Because it's small and exists in darkness in the outer realms. Also, it's just great marketing. Who the hell wouldn't want to read about a goblin planet? Made me click on the link.

Presumably there is evidence that goblins live there

> Named 2015 TG387 and nicknamed The Goblin

I also wondered if it was representative of a class of Goblin objects. I guess the discoverers just liked 'goblin' as a term for something that stays in the dark.

Why "The Goblin"? Because the TG in the name of the object - 2015 TG387.

It's interesting to see how new objects are named: https://www.minorplanetcenter.net/iau/info/OldDesDoc.html

So... every year in August astronomers discover a lot of "The Goblins ;-)".

It's so future objects of the same class can be called "goblinoids".

I assumed it was an extension of the "dwarf planet" metaphor.

It's because the goblins live there, duh :)

It has nothing to do with borderline clickbait - I know people sure didn't click on this link for the faint hope of a fanciful world of hunched over creatures shuffling around doing Goblin things. So yeah, now that we know that definitely isn't the case, it should help to narrow it down

Also, it's easy to intuit it as less massive than a "dwarf" planet.