Garbage in human form
Similar to human garbage, but the difference is that a garbage in human form is in essence a garbage that's pretending to be a human, while human garbage is a human whose worth is about the same as a garbage.
Kitten A: Sally didn't feed us for 3 days. She's such a human garbage!
Kitten B: No, she's a garbage in human form.
Kitten A: what's the difference?
Kitten B: Read urban dictionary.
Kitten B: No, she's a garbage in human form.
Kitten A: what's the difference?
Kitten B: Read urban dictionary.