Officers received a tip the shipment was coming into Chicago, and after getting a search warrant, found the "bundles of synthetic cannabis in shiny silver packages emblazoned with colorful stickers of caricatures," according to police.
Some packages show a monkey holding a banana and are labeled "Monkey Spanker."
Others feature green-haired Batman nemesis "Joker," with the name in green lettering.
"The labels clearly pose a danger with the intent to attract young children," police said in a statement.
Police are still investigating the origin of the shipment.