While poking around the Battle Chess (VGA) executable last year, I came across an undocumented, "/ducks" command-line parameter that the entire internet seemingly bears no mention of. I suspect it was an inside joke, being both a nod to, and supportively-evidenced by, an apocryphal tale concerning the earlier Battle Chess release, described by Stack Overflow user "kyoryu" as follows:

[2010-03-14 23:59:44] kyoryu wrote:

A Duck […]
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A Duck

A feature added for no other reason than to draw management attention and be removed, thus avoiding unnecessary changes in other aspects of the product.

I don't know if I actually invented this term or not, but I am certainly not the originator of the story that spawned it.

This started as a piece of Interplay corporate lore. It was well known that producers (a game industry position, roughly equivalent to PMs) had to make a change to everything that was done. The assumption was that subconsciously they felt that if they didn't, they weren't adding value.

The artist working on the queen animations for Battle Chess was aware of this tendency, and came up with an innovative solution. He did the animations for the queen the way that he felt would be best, with one addition: he gave the queen a pet duck. He animated this duck through all of the queen's animations, had it flapping around the corners. He also took great care to make sure that it never overlapped the "actual" animation.

Eventually, it came time for the producer to review the animation set for the queen. The producer sat down and watched all of the animations. When they were done, he turned to the artist and said, "that looks great. Just one thing - get rid of the duck."

So, what does the switch do?

As far as I've been able to determine, it seems to simply result in the presentation/use of three alternate gameplay cursors.

Namely, the selection pointer becomes a sword:

The "Check" cursor loses a crown and gains a duck:

And, the waiting hourglass becomes a... gratuitously-endowed fraulein.