Good question!
By all accounts (and by all, I'm refering to mine) a Wall Worm is good on a cracker. This assertion has been tentatively confirmed by Brian Atherton. Since that definition is likely not very satisfying to most people, here is a little history.
One day as a teenager I was preparing to leave Brett's appartment. Brett was a childhood friend and the brother of the previously introduced Brian Atherton. Brett and I were preparing to trek up to Westland Mall (a nearby shopping center popular with teenagers who wanted to act like they were there to buy expensive basketball shoes but were in reality there to scope out females).
Just as we were about to leave, Brett's dad boomed out in an ominous and overly dramatic slur something that changed the course of history.* See, Brett's dad was well known for stumbling, shuffling, spiritous imbibing and general swings from indifference to grouchiness. I'm not sure what mood he was in, but I remember him sitting up with intended authority; his eyes were wide in his gaunt face... and he pointed a finger at our general direction.
"Damn kids gunna get yerselfs killed!" he said. I think he was talking to us... but maybe to the ancestors... I wasn't sure. Brett and I turned to leave.
From behind came those ominous words: "Better watch out for those damn wall worms."
And that is the origin of the term.
Anyway... the internet age has come upon us... and I've found that this nifty phrase has caused uneasiness. Firewalls help protect against worms... so some people think that it must be some kind of virus! Now with Facebook and the term Wall monopolized for something we all "own"... it evokes fears of Boob spam.
In any event, Wall Worm doesn't have anything to do with that stuff. It's just a crazy rant I heard as a kid and thought it was unique.
