'STOP Driving Shrooms'?

As I've documented extensively, our neighborhood in Berkeley appears to have one of the highest rates of stop-sign defacement in the United States (if not the world).

Here's one where it doesn't seem like a lot of care/thought went into it. Someone took a "STOP Driving" sign and scrawled "shrooms" beneath it.

You can barely make out the word "shrooms," and it's hard to figure out what that has to do with driving.

It's almost as if the person were mentally incapacitated when they wrote this.