Some anime, especially certain shounen series, seem to have a “throw it in” mentality. They have all kinds of individual elements whose presence in the series seems unrelated to anything else in the series. This results in some really unique worldbuilding.
Dragon Ball is a great example. At it’s core, the central premise of the early parts of the series was “loosely based on Journey to the West and has magic balls that summon a wish-granting dragon”. But just look at everything we see within just the early episodes. Dinosaurs! Hovercars! Animal people! Whatever the heck Puar is! Transforming at the full moon! Then we get robots (including Arale from Dr. Slump), a manwolf (which is not the same thing as a wolfman), someone whose personality and hair color change when she sneezes, and Krillin being able to smell at first but then not after he’s reminded that he doesn’t have a nose. (Okay, that last one falls under Looney Tunes territory.)
(Journey to the West was something of a “throw it in” story to begin with. Size-changing staff! Shapeshifting! Riding on a cloud! Making copies out of hair! Special guest star Buddha! And that’s just in the prologue chapters.)
But one of the most unique elements of Dragon Ball is the capsules. These handy little containers can have almost anything inside them, almost always something bigger than the capsule itself. Who needs to find a parking space when you can just put your car in your pocket? Why bother with a tent when you can carry a house around? They’re never really important to the plot, but they’re too useful to ever stop appearing regularly (unlike Oolong).
But how do capsules work? They can’t just compress what’s inside, because even if they could do that non-destructively, it wouldn’t account for the fact that a capsule doesn’t seem to weigh much regardless of what’s in it. So somehow a capsule negates weight? Or maybe it’s actually some kind of highly specialized teleportation instead of the object actually being literally in the capsule? In any case, I don’t think this one can be explained with anything close to real science.
But have you ever noticed the similarities between the capsule and another famous storage tool, this one from a popular video game with a well known anime? Of course I mean the Poke Ball from Pokemon. They are used on living Pokemon instead of on inanimate objects, but aside from that, they are very much the same. Here, it looks like the Pokemon somehow turns to some kind of red energy when it goes inside, which if anything just raises even more questions. Aside from the obvious impossibility of carrying around some of the heaviest Pokemon, the fact that they negate weight was confirmed in an early anime episode when Onix’s weight was capsizing a ship until Brock recalled it to its Poke Ball. However, it’s not entirely like the Pokemon inside the Poke Ball doesn’t exist while it’s in there, because when Ash caught Muk it still smelled through the Poke Ball.