[[caption-width-right:300: A rather unlikely friendship.]]

->'''Satan:''' Put your socks on, Leo! We're goin' out!

''Leo and Satan'' is an animated comedy created by Website/{{Newgrounds}} user Oney (Chris O'Neill), featuring the exploits of Leo, a preteen boy with a trapdoor to hell in his bedroom, and {{Satan}}, who's [[ExactlyWhatItSaysOnTheTin exactly who you'd expect him to be]], although for the dark lord, he's pretty chipper and childish (but also quite bipolar).

The unlikely duo's first appearance, "[[http://www.youtube.com/watch?v=OchjFx3YgEE Leo and Satan Pancake Doomsday]]", is a simple introduction to Leo's love of pancakes and Satan's love of sugar. Nothing special.

"[[http://www.newgrounds.com/portal/view/530334 Leo and Satan Algebra Aversion]]" is considered the first full episode, in which Leo's struggling with his math homework. Satan tries to help out, with disastrous results.

"[[http://www.youtube.com/watch?v=puy52LVqG7c Leo and Satan Sugar Trip]]" is an overall improvement on length, animation quality and humour, as the pair discover to their horror that they're out of sugar. Whilst walking through town, they bump into a shady man who has what they need...

"[[http://www.youtube.com/watch?v=cHgIQYvv9kk Leo and Satan Trash Hazard]]", has the couple ''borrow'' a board game from the neighbor's trash, which turns out to be a Ouija board.

"[[http://www.youtube.com/watch?v=icXGswYLHSs Leo and Satan - Battery Catastrophe]]" has the duo trying to find the batteries for their game controller.

"[[http://www.youtube.com/watch?v=HHA6J7Nvu0Y Leo and Satan - Leo Goes to School]]" It's Leo's birthday, and that means it's time to start going to school.

The series is without a doubt the most popular work of Chris's, so popular in fact that a few attempts were made to get the series pitched as a series on Creator/AdultSwim. However, [[WhatCouldHaveBeen those attempts fell through]] when Chris learned he [[ExecutiveMeddling may lose creative control]] of his creation if he did. The series has also been on {{Hiatus}} for quite a while, though Chris has said that he is not done making episodes.
!!This web cartoon provides examples of:

* AffablyEvil: For being Satan, he sure is a pretty upbeat and friendly if not somewhat [[MoodSwinger bipolar]] individual.
* AnimationBump: From "Sugar Trip" onward, the animation is improved and even an intro sequence is added in.
* BackFromTheDead: [[spoiler:Apparently, if Leo dies, he'll just go to hell, climb up a tall mountain, and come out through a trap door in his bedroom.]]
** Also, Leo's [[spoiler:parents, who were killed by Satan a few episodes ago.]] The jury's still out on whether or not this is actually a good thing, considering they're both now BuriedAlive [[AndIMustScream and gasping for air]].
* BadassBoast: From the Fanart Corner:
-->'''Leo''': Satan, you're being a jerk.
-->'''Satan''': Whatevahs, bitch. I'm the muthafuckin' Devil.
* BlackComedy: Very much so.
* BloodyHilarious: Plenty of examples, such as [[TearOffYourFace the fate of that bus driver]].
* CatchPhrase: Satan's "You asked for it!"
* ChekhovsGun: [[spoiler:The trapdoor that connects hell and Leo's bedroom.]]
* CrazyHomelessPeople: The murderous drug dealer who gives Leo and Satan cocaine (which they mistake for powdered sugar) in exchange for some of Satan's [[{{Squick}} pubic hair]] so he can [[MakesJustAsMuchSenseInContext disguise himself]] and [[PaedoHunt stalk children at a play ground]].
* CreatorCameo: The drug dealer in "Sugar Trip" is Sean Kiely. [[http://www.youtube.com/watch?v=4-OY76Na8sc He even wears the same garb and uses the same voice in an update video]].
* DeathIsCheap: When you consider that there is a [[spoiler: [[ChekhovsGun magic trapdoor leading from hell to Leo's bedroom...]]]]
* DidWeJustHaveTeaWithCthulhu?: Satan is a [[spoiler:a house-sized red horned dragon]], and well he is Satan.
* ElmuhFuddSyndwome: Leo, at least sometimes. Satan at pretty much all times.
--> '''Satan:''' "Lemme help you with that math homework!"
--> '''Leo:''' "Wow, Satan, that wud be t-t-tewwific!"
** In "Algebra Aversion", one of the math problems on Leo's homework gets in on this.
-->"87a divoided boi seben = what"
* EverybodyHatesMath: Satan tries to help Leo with his Algebra homework... it doesn't go very well.
* EvilSoundsDeep: [[RecurringCharacter Esquire]], the creepy stranger who first appeared in Sugar Trip, has a very deep, growly voice. It's not really a man that you would like to meet.
** Also Satan, when he gets furious.
* ExactWords: Leo's birthday wish is for his dead parents to come back to life. [[BeCarefulWhatYouWishFor Cue shot of said parents' grave]] with [[AndIMustScream muffled screams coming from it]].
* FromBadToWorse: Pretty much whenever Satan helps Leo in his mundane problems.
* TheGhost: Leo's sister is never seen on screen, but is referred to a few times by Leo. [[BuriedAlive As for his parents]]...
* IncrediblyLamePun: "Trash Hazard":
-->''[after Satan crashes through the window]''
-->'''Leo:''' Whoa Satan. Looks like your stealth is out the window! *smile*
-->'''Satan:''' ...[[LamePunReaction shut the]] [[PrecisionFStrike fuck]] [[LamePunReaction up, Leo]].
* ManChild: Satan certainly qualifies.
* MoodSwinger: Satan is prone to them.
* MoodWhiplash: From "Trash Hazard", the show's usual black comedy comes an abrupt halt when [[spoiler:Satan accidentally kills Leo.]] The whole thing is played heavily for drama...until the stinger when [[spoiler:Leo comes out of the trapdoor to Hell, right as rain.]]
* MushroomSamba: Leo and Satan suffer one after taking the cocaine from the homeless man. When its over, [[spoiler: Leo wakes up on a deserted island [[WhatDidIDoLastNight panicking on what just happened while a now giant Satan can be seen attacking a ship in the background for no reason]]]].
* NightmareFace: Satan does this a LOT.
* NumberOfTheBeast: [[spoiler:The answer to Leo's math problem in "Algebra Aversion"]]
* OuijaBoard: In "Trash Hazard".
* PrecisionFStrike: "I DON'T FUCKING KNOW. GOD."
* PromotionToParent: There's enough evidence to suggest that Leo's sister is also his legal guardian. She's the only person he ever mentions when concerned about getting yelled at by an adult, not to mention that the only reference to his actual parents involves them being BuriedAlive.
* {{Satan}}: A very [[ManChild bizarre]] depiction of him.
* SpeechImpediment: Both Leo and Satan are affected by this when they speak.
* ShoutOut: [[Film/TheExorcist "The power of Christ compels you!"]]
** {{Irony}}: [[CrossesTheLineTwice Satan said that line]].
* TheStinger: "Trash Hazard": [[spoiler:[[BackFromTheDead "Now how the heck did I end up in here?"]]]]
* TakeThatAudience: The [[https://www.youtube.com/watch?v=SPQ13u90OPM Fanart Corner video]] is basically Satan calling everyone who submitted shitty artists.
-->'''Satan''': Now if HIV had an art genre, this would be pretty worse.
* TitleSequence: From "Sugar Trip" onward. The intro shows Satan dramatically soar up a mountain in hell and pop up through a door in Leo's bedroom, saying his CatchPhrase: "You Asked for it.".
* VagueAge: Leo says he just started pre-school in one episode, but another episode shows him doing algebra homework.
* WhatDidIDoLastNight: The ending of "Sugar Trip".
* WhatTheHellIsThatAccent: Satan speaks in what can only be described as an infernal bastardization of a Jamaican accent or maybe "Hiberno-Ali-G-Carribean" with a sprinkle of Briticisms. Leo's accent tends to [[OohMeAccentsSlipping vary from scene to scene]], sometimes approximating Satan's accent, sometimes sounding somewhat Irish (which is the least surprising, considering that the Series' creator is Irish) and sometimes sounding generically American.