When you get dirty, black feet indoors regardless of whether you've been wearing socks, shoes, or just taken a shower. This pedestrian condition is quite contagious in that you can develop "the dirty foot" just by being in close proximity with an afflicted carrier.

Showers are of no avail. Sarah Bear Foot scoffs at shower scrubs and pumice stones. All barefoot trespassers beware.
Sarah was often confused with a circus entertainer that walked barefoot on hot coals. It turns out she just had a bad case of Sarah Bear Foot.
by Slap Bet Commissioner July 8, 2012
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