Much likeshithead or poohead, this is a more childish way to say it, before they realised that they wouldn't get banished to the underworld for swearing. Or saying "poo".
Nickname given to bales of marijuana thrown overboard or out of airplanes. Origin is reportedly from members of the USCoast Guard in the area of Southern Florida.
"Base we've got some square groupers floating outside of Miami harbor."