Mario wasn’t always a plumber. Or a Mario, for that matter. Famously, the iconic engineer first appeared in 1981 proto-platformer Donkey Kong, known then only as ‘Jumpman’—hopping around in the company of the eponymous ape and a fair maiden named (ahem) Pauline.

But why a plumber? Because the character’s next game, Mario Bros, would take place primarily underground (read: in front of a black background). Shigeru Miyamoto’s best-selling franchise thenceforward became enamoured with pipes: from those humble origins in the nominal sewers of New York through countless subsequent games, animated TV shows and a movie (unless you like to pretend that didn’t happen), we’ve seen pipes at the beginnings of levels, pipes at the end, Piranha Plants from pipes, pipes you can go down and pipes you can’t, transparent pipes, cannon pipes—well, you get the idea.

Beyond that mighty Mediterranean, pipes seem yet to occupy a key role in video games: from the industrial worlds of sci-fi biggies like Half-Life and Fallout to physics piddlers like Puddle and World of Goo, tubes and systems of tubes quietly dominate the background, often even the logic of our simulated lives. They’re functional, bookending levels and connecting otherwise discrete spaces, and can be used to justify the intrusion into the game world of things from beyond.

Pipes operate a particularly interesting dynamic in two-dimensional games—sidescrollers, traditional platformers, puzzles. Here, the definitively three-dimensional shape of the tube—which acts to transport, to connect, to enable character movement and to enlarge game space—simultaneously limits, severs, hides; for all their incredible possibility, we typically only see the outside of the tube, the hardened shell. As we strive ever toward them like moths to flames, or belch from them like waste, the importance of the device to the gameworld is blocked, censored by its fixity. Resolute in appearance and rarely if ever explored in function, pipes in games are orifices we seek to disavow of their powers.

And yet with Mario we try them all: jumping atop the pipe and pushing down on the gamepad, we want the pipes to work. At the cost of sacrificing our linear progress through the level, and surrendering to an unknown transport, we want to be taken away, disappeared. Bonus levels, warp zones—the spiralling animation and sound effect that Mario’s entrance-exit uses are addictive in their accommodation, in the potential transcendence they offer. It’s a surrender of control we rarely desire, either within games or outside of them. Those pipes we can’t go down—the majority, typically, of a level—are numb, leave us feeling impotent.

Perhaps it’s no surprise that pipes are used to conceal; after all, in the real world they’re typically hidden between walls, above ceiling panels, underground. Marginalised to the spaces between recognised spaces, a cultural decision has been made to choose not to see them. Like the inner workings of our bodies—our plumbing, if you will—we don’t want to be reminded that they’re there.

Or perhaps it’s the contents of pipes that effect their excommunication: waste from our bodies, water and gas that undermine our solidity. Again, we wish rather to impress upon ourselves the idea of a discrete, external, even immaterial form, relegating the rest to darkness.

And yet there need be no decision made amongst these alternatives in games. We are expelled forth from tubular holes and seek oblivion once more in their midst; we are simultaneously repulsed, ashamed by what they carry and what they represent and fascinated by it. We seek to manage the liminality of entrance, yet enjoy our surrender to it. Tubes, then, operate a dual function in our video game lives: concealing, like an enigma, yet cathartic, like an enema.