It sounds unnatural. I wouldn't use it. In any case, you can say something like "František je špatný kluk!", if František is a little child who, I don't know, have just throwned a stone at puppy. You probably won't say that about an adult man. In that case is common to use "zlý", for instance "František je zlý muž." And there is plenty of other expressions, of course :-)
Sorry, I accidentally deleted my comment (and also accidentally downvoted deleted remainder of that comment:-) )
Again: It sounds unnatural. I wouldn't use it. Only maybe, if František is little child who is not yet aware of morality and have just throwned a stone at puppy. "František je špatný kluk" could be used.
"František je zlý kluk" is a bit more natural. I might use "špatný" in a reference to a man or a person, if that particular man or person is bad, but I don't want to sound too rough. "František je špatný muž, pije, kouří, provozuje hazard." (="František is bad man, he drinks, smokes, gambles.")
But in a case that František also beats his wife, I would use "František je zlý muž."
So in a nutshell: "špatný" is a bit soft if you refer to a person. More common is to use it in a reference to things. "Ta pizza je špatná". (=That pizza is bad.") Pizza is feminine, that is why there is used ending -á.
Yeah, but that is another meaning of "špatný". In this case "špatný" = "wrong"/"incorrect"/"different".
"V mém autě sedí špatný František." = "There's wrong František sitting in my car."
Maybe I should have mentioned it. I referred only to character's traits. But in any case, thanks for pointing that out and please, feel free to correct me, I have zero experience in giving advice on learning Czech, besides learning bunch of Albanian guys Czech swear-words :)
The sentence is ok for a multiverse sci-fi; the meaning of spatny is predominantly nespravný=WRONG, not zkažený=MEAN. The sentence in Czech is weird. You would not say it when pointing at someone for being a rascal. For a mean person one would use 'guy' or 'man', verbatim like you wrote...To je František, špatný chlap, špatný člověk.
Did you mean someone talking to František, telling him that something is wrong? There would be a comma before F.: "That is wrong, František." - and quite a different sentence in Czech: the word "wrong" would be an adverb and František would have to be in the vocative because you're addressing him, thus: "To je špatně, Františku."