Fartbombed? Are you saying they're positioning their posteriors next to your letterbox and blasting fetid air through? Quite athletic, we just get the old fashioned 'knock hard and run away' approach.
No, it's a store-bought little pouch you open and it stinks a bit, they left it at the front of my door. Nothing like those crazy toys in the 80s and 90s that got banned lol