In the Series 4 Song Special, he is shown to have a nephew called Scrappus, in the Alfred The Great episode in series 6, he claims to have 7000 cousins, one of whom was eaten by Tang Chinese Empress Wu Zhetian and in both the Series 4 Rotten Romance special and the series seven Ridiculous Romantics episode he has a girlfriend called Ratalie.
Rattus is bubbly, making frequent jokes. He is generally very likeable.
- he was going deaf.
- He had a girlfriend in Series 4 and 7.
- He's a serial killer who killed a pet flea.
- In the Big Proms Party special, he enters the Royal Albert Hall via a sewage drainpipe.
- He often uses a scrap from a baked beans tin as a shield and a wooden sword when talking about battles.
- He once suggested that he would be a millionaire if there were a market for the fleas on his body.