Flying Rhino Junior High

There's a phantom in the basement, the Janitor's a spy, the Principal's a Rhino and no-one's asking why! Dinosaurs are everywhere, a twister's in the sky - it's just another day at Flying Rhino Junior High!

Flying Rhino Junior High is a Canadian animated television series produced by Nelvana Limited and Scottish Television. It originally aired from October 3, 1998 to January 22, 2000 on CBS (as part of a Nelvana-produced block termed the CBS Kidshow, that included Rescue Heroes (based off the Fisher-Price toys, Anatole (about a mouse who worked in a cheese factory), Mythic Warriors, Birdz (which, according to the creator, was Screwed by the Network,the Dumb Bunnies (based off a series of books by the creator of Captain Underpants, Dav Pilkey, but under a false name), a revival of Tales From the Cryptkeeper, and reruns of Franklin (later swapped with Nick Jr.'s Rupert) . Reruns used to be shown on YTV in Canada and STV in Scotland, and on the Cartoon Network in the rest of the UK.

Pretty much every day at Flying Rhino Junior High, the series resident villain Earl P. Sidebottom (an evil boy genius who once got a "D" grade in shop class and so fled in shame to the school's basement, where he now works and lives ala The Phantom of the Opera), along with his evil mutated rat sidekick Ratticus, extracts his revenge on the school by using a machine of his design that can warp reality to transform the school into many strange and dangerous places (he transforms the school into everything from a prehistoric dinosaur-filled jungle to Ancient Rome to a Comic Book to James Bond-esque spy film in various episodes), usually basing what he transforms the school into on whatever relevant topic has come up in school classes (or just in normal conversations around the school) on that day. It's then up to the school's resident Four Man Band of students (namely Billy O' Toole, Marcus Snarkus, Ruby Snarkus, and Lydia Lopez) and their rather large cast of school friends to save the school and the day.

The principal of the school is also a talking rhino in a suit, and the janitor is a former-secret agent humanoid-pig. There seems to be little reason for this outside of the fact that they just are.

It ran for two seasons.

Tropes used in Flying Rhino Junior High include:

Almighty Janitor: Buford, a former CIA agent, now the school's janitor. His expertise is usually called upon to help the students deal with the Phantom's latest reality-warping attack on the school. In one episode, a running Shout-Out to James Bond, he gets to supply the four main students with spy gadgets.
The "B" Grade: Why Earl became the Phantom. A D in shop class was too much to bear.
Butt Monkey: Ratticus is frequently either being beaten up by Phantom or being insulted by him.
Chekhov's Classroom: The Phantom usually transforms the school into a death trap based on whatever lecture (or sometimes just topic of discussion in general) the children were having that day. This naturally leads to the students who were paying attention being the one to get everyone out of trouble.
Edutainment Show: See above.
Everything's Better with Dinosaurs: The first ever episode, "Prehysterical", has the school be turned into a prehistoric jungle full of, of course, dinosaurs.
Frankenstein's Monster: An episode revolves around Earl creating one.
Large Ham: Earl, of course.
Laughably Evil: Despite his ability to change the school into whatever he pleases, it's hard to take Earl seriously.
Meaningful Name: Ratticus is, of course, a talking rat.
Mind Screw: 'Phantom Christmas' revolves around the Phantom receiving one of these.
Minion with an F In Evil: Ratticus
Mirror Universe: One episode had Earl send the kids to a parallel universe where most people's personalities were reversed and their school was a miniature distopia. Raticus hung a lampshade on this, saying that he's seen that in a cartoon before.
Once More with Volume: Used as a Running Gag between The Phantom and Raticus:

The Phantom: What did he/she say????
Raticus: He/She said that...
The Phantom: I HEARD HIM/HER!!!!!

Shout-Out: A lot of them, from small one-liners in the individual episodes, to entire episodes being a shout-out to a specific genre/media type (the prementioned Comic Book and James Bond episodes) to the fact that the Phantom himself is an obvious parody of The Phantom of the Opera.
Status Quo Is God: no matter how many times Earl's computer get wrecked, destroyed, broken or other at the end of each episode, it's back to normal the next one.
Weirdness Censor: The principal is a rhino and the janitor is a pig who used to work as a spy, two facts which (outside of the show's theme song) are never commented upon by anyone. The teachers at the school also never seem to realise that their entire school completely changes into something incredibly dangerous and new on a daily basis (either that or they're in denial.)
X Meets Y: Pretty much The Magic School Bus meets I.M. Meen.