The Sewer Alligator or Sewergator was an alligator that was flushed down the toilet into the sewers. He served as the main antagonist in the episode "Johnny's Royal Flush".
As Johnny was flushed by his dad after being turned into a fish. Once in the sewers, he talks about the things people flush down the toilet. He sees an alligator asleep, bu the gator wakes up because of Johnny, stirs and farts. Johnny is quickly attacked by the hungry alligator bent on eating him. Johnny tries to outmanoeuvre the gator but gets trapped in a dead end instead, only to be quickly saved by Dukey, who had also been transformed into a fish.
The two then make their way to a taxi that houses some fish that are also chased by the alligator. The alligator tries to chew trough the taxi but it doesn't work, so he gets angry, farts, leaves and comes back to cut trough the trunk with a chainsaw. The fish quickly swim away with the gator in hot pursuit.
Johnny's sisters want to fish him out of the sewer but Johnny doesn't want to leave the other fish behind, so they scatter and the alligator grabs the fishnet instead.
The alligator finally corners his prey between himself and the intake pipe for the local sewage treatment plant's maceration chamber. Johnny and the others want to jump from their basin to the next but the water isn't high enough to make the jump, so he leads the alligator to the intake pipe. The alligator manages to catch Johnny in his mouth but soon forgets about eating him when his snout gets sucked in the intake pipe. With the alligator stuck and struggling for his life, Johnny drills his way out of the alligators mouth with a waterproof dental drill and strikes the alligator in his stomach, causing the alligator to fart loudly. The moment that the alligator stopped struggling his snout gets sucked into the pipe a bit more. Because the alligator is blocking the intake pipe with his snout, the water level rises and the fish can jump to the next basin.
The alligator, however, loses his desperate struggle against the intake pipe and is quickly sucked into the maceration chamber's spinning saw blades and reportedly sliced, mashed and microfiltered into lawn fertilizer. The fish cover their ears when they hear the alligator's bones being crushed by the machine.
When Johnny and the other fish are safe, he wonders whatever became of the alligator, the screen than cuts to two sewage workers noticing some alligator-skin bags and jokingly say that it's amazing what people will flush away these days.
- Judging by how big the alligator is, and how frequently he farts in the episode, it is safe to say he usually manages to eat his prey.
- Because of the horrifying way the alligator is killed off, this is the most hated episode in the series. Many villains have done way worst things on purpose than trying to get some food and haven't been sucked into spinning saw blades alive. What makes it worse is that the alligator was probably only killed of so the episode could end with the alligator-skin bags-joke.