"The monkey looks like you."
Translation:Apan liknar dig.
"The monkey looks like you" is a sentence with multiple possible translations with their own implications.
Apan liknar...: In this translation, you get a subject-verb-object sentence, and thus have to go with the object dig or er.
Apan är lik...: This sentence works the same as above.
Apan ser ut som...: Here, the som changes the requirements, making both du and dig (or ni/er) accepted answers. Both are common among us natives, and you can use either. None of them sound unnatural. Some purists consider du to be more correct, but there's not all too much to that argument.
Does that help?