The Invisible Bunnies That Power World Of Warcraft

I’ve written before about a Fallout 4 mod that uses a complex, intertwining network of, er, kitties to make radios work. Turns out, game development is full of stories like that. World of Warcraft, for instance, is overrun with ghost bunnies.

WoW encounter designer Nathaniel Chapman explained it to me via Twitter.

“A lot of stuff behind the scenes that you wouldn’t expect to be a spell in WoW runs using the spell system,” he said. “Spells need casters, so we often have to rely on spawning in an invisible creature to be the one to actually ‘cast’ the spell. Other things that creatures are good at doing would be hard to implement any other way, so we use an invisible creature instead.”

He offered the example of the laser turret in this raid:

Video courtesy of FatbossTV.

“The ‘point’ of this laser turret is actually an invisible creature that is following a player with [a] laser visual and beam attached,” Chapman said. “It’s periodically casting fire zone spells.”

Different games use different invisible creatures. For WoW, it’s mostly bunnies. Chapman pointed me to a list of bunnies in the game, noting that every bunny on the list that’s not categorized as a “critter” is an invisible bunny oompa-loompaing around in the background of WoW‘s endless chocolate factory.

The list, I should add, is 1,000 damn entries long. These bunnies have some incredible names, too. For instance, there’s the Projections And Plans Kill Credit Bunny. I’m also partial to Pony Gun Bunny.

Why is WoW a front for a morally questionable bunny labour operation? The short version is, programmers’ time is limited, and NPCs’ time is not. “Programmer time is extremely valuable, and most of the ‘stuff’ that can be done in a game can be done by NPCs,” said Chapman. “NPCs already have to support things like pathing, casting spells, using weapons, doing various actions to other NPCs, etc. So, while you could in theory have a programmer separately implement every ‘effect’ you wanted in the game with some minor benefit, if you already have a class of thing in a game that can solve your problem, it’s a better use of time to use the existing system.”

“NPCs check off every box in the ‘what I want’ column, except ‘not visible to the player,’” he said. “So you make an invisible creature.”

He noted, however, that this is all case-by-case, and some individual effects and functions are better left to programmers. Principal server software engineer Kurtis McCathern added that there aren’t as many invisible bunnies in WoW as there used to be. The WoW team’s tools have become more refined over time, so they don’t have to duct-tape rabbits to lasers as much anymore.

“Sometimes,” McCathern said, “you don’t know designers need a kitchen until they have made ramen in a flower vase with an iron.”

Other designers pointed out that games they have worked on or played were also built on the haunted remains of pet cemeteries:

… Guild Wars 1 used it (in particular, I wrote tons of those scripts), iirc World of Warcraft did it for a while too

— Katelyn Gadd (@antumbral) January 23, 2017

iirc the rideable horses in LOTRO were actually a pair of pants you equipped

— Chris Maire (@dinosaursssssss) January 23, 2017

Work halted while we attempted to clear the invisible cats out of the building. The ones who climbed into the rafters were most difficult

— mcc (@mcclure111) January 23, 2017

So there you go. If you think you’re alone in your favourite game — quietly taking in the view, breathing the gentle spring air, and shouting your secrets as loudly as you can — you’re probably not. Beware the bunnies, for they see all.

This story was originally published in January 2017.