The Catillac Cats

The group is headed by Riff-Raff, a tan, short, tough, streetwise alley cat.

Mungo is a large, dim-witted gray cat who acts as a lackey for Riff-Raff.

In the flashback episode "Christmas Memories", it is revealed that Cleo is, in fact, one of the Catillac Cats herself, even going as far as to indicate that she coined the name.

[4] Although both Heathcliff and The Catillac Cats are set in the fictional city of Westfinster, only Hector, Wordsworth and Mungo appear in both segments.

Riff-Raff appears with Hector and Mungo in a crowd cheering for Heathcliff in season one, episode nine.