Fallout 4, cats, and in-game radio stations might not sound like they have much in common, but for one mod, they go hand-in-hand. One gamer has uncovered the peculiar way in which a very popular radio mod for Fallout 4 works.

Fallout 4‘s Old World Radio Boston mod is one of the most popular audio mods in the game, with over 300,000 downloads to date. However, the creator’s method for adding an extra radio station to the game that continues to play music in real time – even when a player changes the channel – is surely an odd one. As uncovered by Twitter user Chris Boyd, modder Brandoman has utilized invisible cats in order to make the mod work.

According to an explanation by Brandoman, the invisible cats are a necessary part of running the radio station. Like other radio stations, Old World Radio Boston continues to change tracks in real time, even when a player turns off their radio or changes stations. However, to make this happen for a mod, it was necessary to use an object that could be spawned near the sole survivor that would manually shift the tracks:

“To give you a little clarification, I spawn an invisible, silenced cat 500 units behind the player when an inactive radio station switches tracks in the background. The cat acts like a settlement radio receiver, and its role is to keep alive the inactive radio station so it continues to the next track even if you’re listening to another station. Just like if it was a settlement receiver somewhere near the player. In normal circumstances the cat doesn’t make sound, it is silenced, it is invisible, and it is deleted from the game world after 3 seconds.”

fallout 4 cat desk

To make matters even weirder, some players experienced a bug where Fallout 4 would spawn multiple invisible cats that wouldn’t vanish as they should. While Brandoman has since resolved the problem, the reality that a radio station is broadcasting to the wasteland via Fallout cats is certainly unexpected, to put it mildly.

Game developers work hard to make the underlying programming and mechanics hidden from players. Yet despite a full team of professionals and game testers, Bethesda itself managed to leave plenty of puzzling bugs in the Fallout 4, too. Early on, gamers experienced oddities like the sole survivor’s companion Piper seemingly lying dead on the ground while continuing to talk, or glitches that would warp the player while using V.A.T.S.

While it’s rather amusing that invisible cats are utilized in order to allow the player to continue listening to this radio mod, it’s also rather ingenious. Chances are the vast majority of players who have used the mod never noticed the brief presence of an invisible cat stalking them through the wasteland. Those who were subjected to the glitch and stumbled into a multitude of invisible cats, however, may have questioned their sanity.

Have you downloaded this mod? Were you surrounded by a horde of invisible cats? Let us know in the comments.

Fallout 4 is out now for PC, PS4, and Xbox One.