Superman's latest week has been so odd that he wonders if he's going crazy. Things seem to be happening that no one else can see, and mixed up in it is a strange little man. Then the Man of Steel discovers that the bizarre occurrences have been caused by a 5th-dimensional imp, Mr. Mxyzptlk, who unfortunately wants to play games with him. The only way to get rid of him is to force him to say/spell/etc. his name backwards, but this only works for 90 days at a time, and each time Mxy gets angrier and more determined to beat him. Can Superman get rid of this exasperating imp once and for all?
This episode contains examples of:
- All Myths Are True: Mxy claims to have inspired the stories about imps, genies and leprechauns.
- Alternative Calendar/Exploding Calendar: As Mxy builds his giant robot, the months of "George" and "Relish" go by, until he's finally ready on the 30th day of "Pants".
- Batman Gambit: Superman plays Mxy every time after the rules are set, especially in their last battle.
- DVD Commentary: Received a video commentary for the Volume 2 DVD set. On it, Paul Dini refers to this as his favorite episode.
- Great Gazoo: Mr. Mxyzptlk.
- It Is Pronounced Tro PAY: When Clark initially mispronounces his name, Mxyzptlk corrects him and provides the handy mnemonic (which he illustrates using his powers) "Mix", "Yes", "Spit", "Lick".
- Jerkass: Mxy.
- Just Ignore It: Before the final confrontation of the episode, Clark puts on a great show of indifference to Mxy transforming the Daily Planet staff into animals and threatening to expose Superman's secret identity. He thus goads Mxy into raising the stakes from a ninety-day reprieve to a permanent departure.
- Ms. Fanservice: Gsptlsnz
- Mundane Utility: Superman uses his heat vision to shave.
- Mythology Gag: Mxy turns Jimmy into a turtle. In the comics, a growth ray combined with a turtle turned the hapless kid into a giant turtle boy.
- Mxy turning Lois into a horse could be a nod to her time as a centaur.
- Lois confirms her sister Lucy is in this continuity.
- Mxy using his powers to make Streaky the cat fly.
- The strip "Mr. Mxyzptlk" is said to be written by Jerry Siegel and Joe Shuster, Mxy's creators (not to mention Superman's).
- Mxy's claim of being the source of stories about imps, genies, and leprechauns is a nod to Lois and Clark.
- No Indoor Voice: Mxy. What do you expect from Gilbert Gottfried?
- No Ontological Inertia: After Mxy is banished for good, everything returns to the point immediately before he starting turning the staff into animals.
- Noodle Incident: Mxy spends three months creating a giant robot to fight Superman. We never hear about what happens, but he pops back into the fifth dimension a few seconds after leaving.
- Not Distracted by the Sexy: Gsp tries to get Mxy's attention with various come-hither outfits, but he remains focused on building his giant robot.
- Obfuscating Stupidity: Superman pulls this on Mxy twice. First is when he claims not to know which one of them is supposed to say Mxy's name backwards. Second is when he makes several writing mistakes, getting Mxy to spell-check and mark off the necessary letters.
- Oh Crap: Mxy several times.
- Reality Warper: Mxy, unfortunately.
- Screw This, I'm Outta Here!: After Mxy turns the staff into animals, Superman just gives up and leaves. That was part of his plan, though.
- Ugly Guy, Hot Wife: Mxyzptlk and Gsptlsnz.