A number of the What Ifs are hilarious due to the completely insane, but perfectly logical, conclusions (and, sometimes, the sheer insanity of what is being logically considered in the first place). Others are hilarious for the irrelevant but amusing tangents the author sometimes goes off on.
of course, in that case, the question wasn't exactly straightforward. Still, the conclusion, in context, is arguably one of the funniest things on the site; A careful reading of official Major League Baseball Rule 6.08(b) suggests that in this situation, the batter would be considered "hit by pitch", and would be eligible to advance to first base.
A Mole of Moles. No insane ending, but it nevertheless involves a moon-sized ball of meat and fur that periodically erupts in plumes of boiling guts.
Glass Half Empty. The standard optimist-or-pessimist question leaves people with shards of broken glass embedded in their faces.
Tie Vote. A question about elections ends with this gem, with an image to match:
...when one of the Florida electors reaches into the hat to draw a name, he or she is struck by a falling cocaine bale, the hat is hurled away within the next few seconds by a tornado, and the elector is obliterated minutes later by a meteorite impact.
Longest Sunset kicks off the article by defining what qualifies as a sunset and what doesn't. Examples of the latter include the sun crossing the horizon partway and then reversing direction, the sun splitting in two and half of it setting, the sun landing on the horizon and hatching like an egg (Alt Text: "you bred sun-raptors?"), and a square sun that doesn't get a chance to do anything before the narration cuts it off (Alt Text: "aww, man, you didn't even let me try").
Another one links to the Wikipedia page for Cetacean.
Sunless Earth. After a long list of the surprising benefits of a lack of sunlight, the ending bluntly points out we'd end up freezing to death.
It's the Sun. We need the Sun.
Drain the Oceans. Sure, the oceans would be gone and with them most of the biosphere and planetary habitability, but the real major change is The Netherlands conquering the planet.
In Drain the Oceans: Part II, after the ocean is finished being deposited at Mars, the Netherlands use the ocean-draining portal to conquer Mars as well.
Dropping a Mountain calls back to Drain the Oceans. The mountain is dropped from high enough that it pulls an orbital slingshot around the Earth, and crashes into New Netherlands, the now-Dutch-and-watery Mars.
At some point, Munroe started getting creative with his citations. Clicking the numbers in Random Sneeze Call reveals these gems:
However, given that sneezes are far more common than murders, 2 Citation: You are alive. (...)
[The control group] was given no allergens at all; they just sat alone in a room for a total of 176 20-minute sessions. 5 For context, that's 490 repititions of the song Hey Jude.
The subjects in the control group sneezed four times during those 58 or so hours, 6 Over 58 hours of research, four sneezes were the most interesting data points. I might've taken the 490 Hey Judes. which (...)
The X-15 aircraft reached space just by going fast and then steering up. 3 Make sure to remember to steer up and not down, or you will have a bad time.
The ISS moves so quickly that if you fired a rifle bullet from one end of a football field, 7 Either kind. the International Space Station could cross the length of the field before the bullet traveled 10 yards. 8 This type of play is legal in Australian rules football.
When doing the research for Falling With Helium, Randall made so many requests to Wolfram Alpha that he got his IP address banned. The image of his ban-appeal request is icing on the cake.
Please provide us with detailed information about what you were trying to do (e.g. type of project, query types, etc.):
Calculating how many rental helium tanks you'd have to carry with you in order to inflate a balloon large enough to act as a parachute and slow your fall from a jet aircraft.
Soda Planet concludes with a diagram of a person drinking directly out of an apatosaurus. With a straw.
Another image describes increasingly large stars as "stars that are heavier, bigger, bluer, younger, (the rest is crossed out) harder, better, faster, stronger". These are referred to as "Daft Punk stars" in the main text afterwards.
Citation #5 in Paint the Earth goes off on a tangent listing things that are not buildings.
EXAMPLES OF THINGS THAT ARE NOT BUILDINGS: Ducks, M&Ms, cars, the Sun, cuttlefish, microchips, Macklemore, lightning, goat blood, zeppelins, tapeworms, pickle jars, those sticks you use to toast marshmallows, alligators, tuning forks, minotaurs, Perseid meteors, ballots, crude oil, sponsored tweets, and catapults that throw handfuls of engagement rings.
The 237 mph diagram, comparing two circles of nearly equal size: "Bag Full of Golf Balls", and Earth ... which is labelled "Ball Covered With Golf Courses."
Growth Rate states that if children kept growing at the rate they do just after birth, they would be as tall as Darth Vader by the time they were three. Then there is a picture of Dark Vader and a three-year-old that's caught a beetle.
Billion-Story Building, in which Randall attempts to explain to a four-year-old why building a billion-story building is impossible. It's quite hilarious, because you can tell he's making a genuine effort to let the young girl asking the question down gently, but what makes it even funnier is the utter absurdity of such a building once Randall draws a billion-story-tall skyscraper and compares its size with Earth (It's tall. Really tall. Like "reaches-past-the-Moon" tall.)
In "Vanishing Water", Randall is asked what would happen if all the oceans and lakes on Earth were to instantly disappear. In the Alt Text of one of the pictures, he grumbles that this would cause yet another situation where all life on Earth would die horribly.
"Why can't the questions ever be, like, 'what if I saw a really good movie' or 'what if I adopted a puppy'?"
In "Global Snow" a small duck pond full of an inch worth of water made into snow is shown shrinking due to it's own weight with a small duck in winter gear sitting on top waiting for it to become a pond again.