It's been said that video games are all smoke-and-mirrors — elaborate feats of code and trickery that imply possibilities far greater than what you're actually able to do. Sometimes, though, the truth is much stranger. Sometimes the truth is radios powered by invisible cats.
Old World Radio: Boston is a mod for Fallout 4 that adds more than 30 new radio stations to the game, some of them with professional-quality voice acting. It's an impressively polished project that has been downloaded over 300,000 times. Now let's take a look under the hood. Responding to a bug complaint where a player suddenly had to contend with a seemingly immortal spectral kitty cat, one of the mod's creators, cdante, explained their method (the exchange took place a little while back, but was unearthed today by Chris Boyd):
"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," they said. "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 three seconds."
"In very rare cases, though, some of the stations bugs out the first time you install the mod, and it causes to spawn cats rapidly," cdante added. "That is what you've experienced. I tested this version of the mod for nearly two weeks, and I only bumped into this problem once, and as soon as I activated all the stations in my pipboy, the bug fixed itself."
Fortunately, cdante has since released a fix for the issue. They also posted a tech demo video of their method:
The short version? Don't worry: Invisible cats won't knock you out of stealth, even though tip-toeing around, blasting the greatest hits of the '40s, '50s and beyond seems like a surefire way to get caught. Fallout logic!
Of course, modders are hardly alone here. Game engines are complex, unwieldy beasts at the best of times, and developers staple together Frankenstein solutions on a regular basis. Remember the Fallout 3 train monstrosity?