Manuel keeps a pet rat named Basil. In the episode “Basil the Rat,” Manuel acquires what he believes is a Siberian hamster, only for it to be revealed as an ordinary rat; he names it after his employer, Basil Fawlty.
The pet becomes central to the episode’s farce when it escapes from its cage and runs loose through the hotel. Manuel is genuinely attached to it, while Basil and Sybil are horrified by the hygiene risk, especially because a health inspector is expected. The staff must catch the animal before it is discovered.
A common mix-up is to remember the animal as a hamster, because that is Manuel’s original belief. The joke depends on the gap between his understanding and reality: the creature is not a ferret, mouse, or hamster, but a rat. The episode also connects the animal to the series’ recurring theme of Basil’s inability to control the hotel’s chaos.