Atlanta ? The head of the Cartoon Network resigned Friday over a publicity stunt that caused a terrorism scare in Boston.

In a memo to staff members, Jim Samples, general manager and executive vice president, said he regretted the incident and felt “compelled to step down, effective immediately, in recognition of the gravity of the situation that occurred under my watch.”

Dozens of blinking circuit boards showing a cartoon character giving the finger were planted in 10 cities as part of a guerrilla marketing campaign to promote the cartoon “Aqua Teen Hunger Force.” In Boston, the discovery of the devices Jan. 31 led police to shut down bridges and highways and send in the bomb squad.