I explained the dangers of Selfie Tennis to my friends before they played. I told them how many people had been hurt, and how many controllers had been broken. They paid attention; they're always respectful of hardware I have for coverage that's hard to replace and we were having a good time playing games together.

We had our first injury five minutes later. The controller was scuffed, a hole was nearly punched in the ceiling, and a good friend lost a bit of skin on his knuckle. I took the picture at the top of this article during that session.

Selfie Tennis is the reason one of my Vive Pre controllers rattles. I believe a sensor was knocked loose after I slammed it into the ceiling. I've never hurt myself playing the game, but I've busted equipment. Multiple friends have lost skin on the walls and ceiling. The danger is very real, if limited to annoying bumps and scrapes.

I still play it daily. I still show it to people and, after warnings, many of them still hurt themselves. What the hell is going on?

The dangers of VR

Selfie Tennis is a sort of surreal take on the sport of tennis, except you play with and against yourself. One motion controller is the racket, the other spawns tennis balls, and you teleport over the net to hit each ball back to yourself. It's not a game of trying to get the ball away from your opponent anymore; now you must hit it in such a way that you'll be able to continue hitting it for as long as possible.

It may look silly, but it's comfortable to play for long stretches, and hitting the ball back and forth with yourself is surprisingly meditative. It's one of the best games for the HTC Vive, and is available now on Steam for $19.99.

The problem is that you're swinging your hands around while moving quickly to hit each ball back to yourself. It's hard to fight your natural instinct to jump up and raise your arm as high as possible to hit the balls that fly over your head. Those shots usually end in injury to your play space, the controller or yourself.

Dangers of VR are real, folks. pic.twitter.com/tNBtg1VM7j — Adi Robertson (@thedextriarchy) March 31, 2016

"You know what's amazing? It hurts them and they love it!" developer Horatiu Roman told me on a video call with VR Unicorns, the team behind Selfie Tennis. "It's not just that it hurts them, but they love it! They get back to it!"

"This is pretty much our safest game," Julie Heyde said, who offered "chicken bitch" as her official job title.

I asked if perhaps the game should come with a warning about potential injuries. "Well, it's not Oculus, right, so we don't really need to get a warning, do we?" Heyde asked. "The fact is, if people want to hurt themselves, we should just kind of let them."

Selfie Tennis actually came from a late night working on another game, when the team began to yell out silly ideas to each other. One of them was Selfie Tennis, and it tripped something in Roman's head. The rest of the team went to bed, having already forgotten about the idea. They woke up to a working prototype.

"Milan [Grajetzki, who works on design, sound and music] comes up with a crazy idea, and if I find it amusing I make it in a few hours," Roman said to explain their process. "The first iterations of Selfie Tennis, as you might imagine, were pretty broken. But the teleportation seemed to work, especially once we knew to delay it a bit."

It would seem like teleporting the player back and forth across the court would make people sick, but the symmetrical nature of the court, combined with the slight time delay, removes any hint of nausea. It's also easy to understand what to do once you teleport: You have to try to hit the thing moving toward you. It's primal.

People loved the early versions of the game, and the Unicorns were able to continue honing the experience through constant iteration and updates pushed to players with pre-release Pre hardware. And those players began hurting themselves.

@VRUnicorns Vive needs ceiling boundaries as well! Ha ha. Too... much... fun! Casualties pic.twitter.com/WcLgs79lqz — Brandon Sellers (@bms2993) March 11, 2016

This situation is interesting for a number of reasons. The game injures people. The people getting hurt almost always find it funny. There is little to no warning within the game.

Everyone involved seems to find it hilarious. I've lost one controller, a bit of ceiling and the hands of a few friends to the game. We all have a good laugh when I show them the scuffs of my new controllers. No one seems angry or concerned. We have a new technology, a game that is actively beating people up ... and the result seems to be hilarity.

"I always say we're based in Denmark! Sue us, try it man. " Heyde said. "We're not in the U.S.; nothing will go through in Denmark. But at the same time, now that we've signed with Devolver, I guess it's their problem. Fork Parker will have to deal with it."

Indie publisher Devolver Digital is indeed working with the game, so I reached out to its "fictional" CEO, Fork Parker, for comment on the issue of injuries.

"Selfie Tennis League (STL) commissioner Fork Parker denies all allegations that there is a direct link between SelfieTennis and injuries sustained to the players during their time in the league," reads the statement Polygon received.

"The STL has been on the forefront of promoting and funding independent research on these complex issues. Further, the data from the Virtual Reality Injury (VRI) Committee studies have drawn no definitive conclusions in its research on player health and safety. All of the current policies relating to player medical care and the treatment of SeflieTennis injuries have been carefully developed in conjunction with independent experts on our medical committees, the STLPA, and leading bodies such as the CDC."

So I mean, they're taking it seriously.

The VR Unicorns team has a beam in its studio ceiling that people often hit when demoing the game. Sometimes the developers are lucky enough to be showing the game in a location where they can play outside, removing all constraints from vertical motion. They tell me Valve is working on a ceiling for the Vive's chaperone system so players can easily see all four sides of their play space and perhaps be more careful about hitting the ceiling.

The VR Unicorns also make sure that people are using their wrist straps, as they have a bad habit of losing control of the motion controllers and having them fly across the room. Which is, of course, another danger of the game. "Milan is the only one who hasn't thrown a controller yet," Heyde confirmed.

"I think you can learn to be a little more composed, and you need to learn that maybe. Maybe it's a good way to learn that?" Grajetzki said. "To slam into something."

So learn to pay attention to your movements and be mindful of your body and play space. Clear the area of any tables or chairs you might hit. And when you do hurt yourself? Send them a tweet. They love to hear about it.