Attack of the Mutant Guppies is an episode from the second season of Garfield and Friends.
Garfield's story of giant radioactive mutant guppies turns out to be real after Nermal gets him to investigate.
In the middle of the night, Nermal is sneaking into the kitchen to grab something from the fridge. Unknown to him, Garfield has set a surveillance camera on the top of the fridge to check for snackers. Just as Nermal is about to grab something, Garfield stops him and threatens to send him to Abu Dhabi if he touches any of the food.
Nermal asserts that he is grabbing food for his pet guppy which he was holding during his secret raid. Garfield claims that Guppies can be dangerous. He then tells a story about Giant Radioactive Mutant Guppies living in the sewers. According to him, they were originally pet guppies that kids did not want as birthday presents. They would eventually put them down the drain and into the sewers, where they would mutate from all the chemicals that humans would dump in there as well. Nermal then says that the story is not true and that they are nonexistent. Garfield then goes to bed thinking the story will get Nermal out of his food for a while.
Later that night while looking at his guppy, Nermal becomes worried that Garfield's story may be true, and is unable to sleep as a result. He then wakes Garfield and asks him to take him to the sewer for mutant guppies there. Despite admitting that his story was made up and trying to get some sleep, Nermal still tries to get Garfield to check the sewer. Eventually he gives up when Nermal tries to play "Binky's Greatest Hits", and the two cats enter the sewer.
For a while they find nothing in the sewer; they then hear roars in the water and soon mutant guppies emerge from the sewers. Realizing that his tall tale was real, Garfield and Nermal scramble to escape the sewer and evade them, only for the guppies to quickly swarm the two. Nermal asked if this is a dream, to which Garfield checks his bed and finds it empty, implying that it is not a dream.
By now the guppies have cornered the two and Garfield decides to take drastic measures. Running into the garage, he comes out with a barrel full of white stuff which Nermal thinks it is a substance to reverse the radiation. Garfield states that it is tarter sauce, thus intending to eat the guppies for a midnight snack. Realizing what he is about to do, the guppies race back to the sewers with Garfield hot on their tail. Eventually they see the guppies racing down the sewers with Nermal wondering where they will go. Garfield says that by morning they will be miles away, never to be seen again. He later says it is better that way without enough French fries to go with them.
- Giant Radioactive Mutant Guppies (one voiced by Frank Welker)
- Girl (voiced by Desirée Goyette)
- Nermal's Guppy
- The guppies show up in the following U.S. Acres Quickie. They made their way to Orson's farm through a water well. After scaring Orson and Wade away, the guppies decide to get a guest shot on Muppet Babies.
- Odie appears in the title card.
- Nermal prepares to play Binky's Greatest Hits to get Garfield out of bed.