Rattus is bubbly, making frequent jokes. He is generally very likeable.
- he was going deaf.
- He has a girlfriend in Series 4
- 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.