An awful relic from less enlightened times, or a sign that the attitudes from those times have not gone away completely. Comic relief characters in the Small Annoying Creature or The Scrappy mold whose strangeness in appearance and behavior is put down to their being of a different race or ethnicity to the heroes. Often highlighted by their being extreme gonks in an otherwise normal cast. Sometimes, ironically, they were put in precisely because the creators wanted some diversity in the cast. This is definitely one case where Monochrome Casting would have been a lot less offensive.