Ratagator

The Ratigator is a large, mutated creature, resembling a mixture of both a rat and an alligator; the Ratigator also happens to be a friend of Mario and Luigi in The Super Mario Bros. Super Show!, often appearing to visit them in their home in Mario Brothers Plumbing.

Appearances
The Ratigator's first appearance in The Super Mario Bros. Super Show! was in the live-action segment "Alligator Dundee", where the Ratigator, having been frightened by something in its sewer home, rushed into Mario Brothers Plumbing, where it encountered Mario and Luigi. Seeing the Ratigator distressed, Mario and Luigi comforted it and learned that something had frightened it, only to be surprised when the Ratigator quickly speed away back into the sewer upon the arrival of a man named Alligator Dundee.

Later, Alligator Dundee, who was revealed to be hunting the Ratigator, entered it's sewer home in search of it while Mario and Luigi, having surmised that Alligator Dundee was what frightened the Ratigator earlier, reluctantly helped him. Finding the Ratigator, Alligator Dundee, having seemingly failed to lure it out into the open with a tuna sandwich, seemingly got into a skirmish with, but seemingly succeeded in getting the Ratigator to try and chase him out of the sewer.

In the end, it was revealed to Alligator Dundee, after being accidentally captured in a net by Mario and Luigi, that the Ratigator was their pet; learning this, Alligator Dundee decided to stop his hunt for the Ratigator and create a major motion picture detailing his hunting of it, while also decided to rename himself "Ratigator Dundee". The Ratigator, having heard Alligator Dundee say it's name, rushed forwards out of the sewer and, along with letting Mario and Luigi pet it, also allowed Alligator Dundee to pet it as well.

The Ratigator next made a small appearance in "Mario Hillbillies", where it allowed the visiting Ellie Mae to pet it; when Ellie Mae asked Mario Joe and Luigi Bob, who were posing as their cousins, Mario and Luigi, what the Ratigator's name was, the two responded with the names "Zeke" and "Luke". Similarly, the Ratigator plays a small role in the following episode, "Baby Mario Love", where it appears, carrying a leash in it's jaws, trying to convince Mario to take it for a crawl, which Mario refuses to do, stating he's already taken the Ratigator for a crawl earlier; later, as Mario attempts to tell Luigi that their lives lack glitz, glamor and a certain "je ne sais pas", Luigi, apparently not comprehending Mario's last statement, tells him to watch his mouth, saying the Ratigator is present.

Trivia

 * The Ratigator's name is a portmanteau of the words rat and alligator, the two animals which it resembles.