battery pack
n.— «Brannon was described by a local gang investigator as a “battery pack” within his gang set, a term used to describe a member who is always on the streets, willing to do anything for the gang. The investigator said Brannon has been sent a variety of gang tasks, from murders to decoy tasks.» —“Net widens for accidental fugitive” by Andrew Kitchenman The Times (New Jersey) June 14, 2007. (source: Double-Tongued Dictionary)
Further reading
Sean in Oneonta, New York, says that when he was growing up in New Jersey, his family would pile in the car and set off on a surprise adventure, whether a short distance or long, and the kids would be told only that they were going on Buxtehude...
Amid court-ordered busing in the 1970s, a middle-school teacher tried to distract her nervous students on the first day of class with this strange assignment: find a monarch caterpillar. The result? A memorable lesson in the miracle of metamorphosis...