I am struggling with translate the particular sentence in the game

[Anchovy01]

Hi, I am the member of an amateur game translating team.
While translating the game, I found the sentence that I couldn't even get a clue. The sentence is following:
"This Duplicant might actually be several blackholes in a trenchcoat"
Could anyone explain what that means? Do I have to think that blackhole as literal meaning or is it some kind of meme?

[ImDaMisterL]

That sentence is for the Duplicants with the negative trait of eating a lot.

I guess any common saying of your language regarding someone that eats way too much would do, like "They might have 7 stomachs!" or something like that

[Anchovy01]

thanks dude, you saved us. We almost translate it as 'he has like mysterious gigantic sucker in his coat'. XD

[PaladinOfKaos]

ImDaMisterL is right, and for an early draft of the translation any joke about eating a lot will probably work, but there's a few aspects to the english form of the joke:

1. The space reference of "black hole" (because it's a space game!)
2. Black holes, of course, consume everything around them (because it's the trait for dupes that eat a lot)
3. A common gag in english media where a person turns out to be something else hiding in a big coat. See http://tvtropes.org/pmwiki/pmwiki.php/Main/TotemPoleTrench

The phrase in the game is not at all a common english phrase for eating a lot. Most of what makes it funny is the mental image of a black hole poorly disguising itself as a person. Jokes are always hard to translate, but I think if you want to try to capture the feel of the game you should try to do something similar, or as much as you can in your language.