"rat child" is used as an insult to a person who is someone who you do not like or has annoyed you. They are often a social outcast and a scum of the universe. They are often younger than yourself and likely to have been born because of an accident.
Tom is such a rat child, he pissed all over my chips.
But frisbee is a brand name, so it should be described as a novelty flying disc. Can be abrieviated to NFD. Novelty flying disc has become a well used phrase is many parts of the UK. Originally from an episode of the simpsons.
Em: What shall we do at the beach?
Russ: Let's play Novelty Flying Disc!!!