A road construction sign in Boulder, Colorado was recently hacked and reprogrammed to read, "WARNING DALEKS AHEAD."

"The sign, on eastbound Arapahoe before 48th Street, displayed the mutant warning Tuesday night and into Wednesday morning, but the message was fixed during the day to warn of delays ahead," The Boulder Daily Camera reports. "Pranksters also struck road signs in Boulder last spring to warn motorists on Foothills Parkway that there were 'ZOMBIES AHEAD.'"

"The Daleks, the extermination-loving tin pepperpots from British sci-fi TV show 'Doctor Who,' have clearly picked up on the program's growing popularity in the United States, and allegedly invaded Denver, Colorado," writes Sophos' Graham Cluley. "Mystery surrounds how practical jokers managed to meddle with the electronic construction sign along Arapahoe Road in Boulder, Colorado, as the local department of transportation is stridently claiming that the device was properly secured."

That's a key difference from the "ZOMBIES AHEAD" hack last March, when the control box for the sign had apparently been left unlocked, making it extremely simple to access.